CHEMISTRY  SIMPLIFIED. 


CHEMISTRY    SIMPLIFIED. 


A  COURSE  OF  LECTURES  ON  THE  NON-METALS, 

BASED  UPON  THE  NATURAL  EVOLUTION 

OF  CHEMISTRY. 


DESIGNED  PRIMARILY  FOR  ENGINEERS. 


GEORGE  AUGUSTUS  KOENIG,  Ph.  D.,  A.  M.,  E.  M., 

PROFESSOR  OF  CHEMISTRY,  MICHIGAN  COLLEGE  OF  MIXES,  HOUGHTON,  MICHIGAN. 


ILLUSTRATED  BY  ONE  HUNDRED  AND  THREE  ORIGINAL  DRAWINGS. 


PHILADELPHIA  : 
HENRY  CAREY  BAIRD  &  CO  , 

INDUSTRIAL   PUBLISHERS,  BOOKSELLERS  AND    IMPORTERS, 

No.  810  WALNUT  STREET. 
1906, 


COPYRIGHT,  BY 

GEORGE  AUGUSTUS  KOENIG, 
1905. 


PEEFACE. 

IN  these  lectures  to  mature  beginners  in  Chemis- 
try, the  fundamental  idea  has  been  followed  to 
unroll  before  the  student  the  knowable  nature  of 
bodies  as  an  ever-growing  and  spreading  picture, 
and  not  as  a  finished  work  handed  down  by  the 
great  masters.  When  I  say  mature  beginners,  I 
mean  that  in  my  estimation  chemistry  should  not 
be  taught  at  all  to  boys  and  girls  before  their  full 
mental  growth  has  been  attained,  fully  aware  of  my 
isolated  position  in  the  present  evolution  of  schools. 
Only  the  mature  mind  follows  with  growing  interest 
the  unfolding  of  such  a  picture,  and  absorbs  it  as  a 
living  thing. 

In  following  this  fundamental  idea,  the  usual 
systematic  classification  .had  to  be  abandoned.  It 
will  be  seen  that  the  beginning  is  made  with  bodies 
of  familiar  acquaintance  such  as  the  common  metals, 
but  these  metals  are  not  postulated  as  elements  or 
simple  bodies ;  they  are  merely  objects  for  experi- 
mentation in  allowing  the  equally  familiar  bodies 
of  air  and  water  to  act  upon  them  under  the  familiar 
impulse  of  heat.  Noting  the  changes  thus  wrought, 
the  mind  questions  and  seeks  answers.  Answers 
come  by  carefully  laid  experiments,  but  always  in 

(v) 


295603 


VI  PREFACE. 

such  a  way  that  no  agent  of  unfamiliar  nature  is 
called  in  to  aid.  Such  a  scheme  is  essentially  his- 
torical, for  the  successive  generations  of  chemists 
have  been  working  in  exactly  this  way.  They  saw 
and  raised  questions.  Their  answers,  being  pre- 
mature in  so  far  as  they  brought  into  play  unknown 
agents,  were  often  wrong,  had  to  be  set  aside  and 
much  modified  by  subsequent  investigations.  Thus 
also  in  these  lectures,  questions  are  raised,  but  not 
answered  at  once,  although  perfectly  well  known, 
because  the  student's  knowledge  has  not  reached 
the  required  fullness.  In  the  chapters  on  green 
vitriol  and  on  common  salt,  as  well  as  on  potash, 
the  reader  will  find  the  application  of  the  funda- 
mental idea  fully  elaborated. 

Generalizations  from  the  experiments  are  always 
drawn,  though  I  have  avoided  the  term  law.  The- 
orizing upon  molecules  and  the  structure  of  mole- 
cules, ions  and  electrons  I  have  omitted  altogether. 
No  beginning  student  can  be  capable  of  drawing 
inferences  for  himself  concerning  these  matters. 
They  should  only  be  brought  before  the  student  at 
the  end  of  his  school  work,  if  he  intends  following 
chemistry.  To  bring  them  before  proposing  en- 
gineers, seems  unnecessary,  if  not  unwise,  and  these 
lectures  are  delivered  to  engineering  candidates, 
more  especially  mining  engineers  and  metallurgists. 
To  them  the  theories  can  be  of  no  help.  They  want 
to  know  the  practical  consequences  which  must 
follow  from  the  presence  of  certain  material  condi- 
tions. They  must  be  trained  to  inquire,  and  de- 


PREFACE.  Vll 

duce  from  given  conditions.  The  chief  tendency 
of  the  lecture  course  is  to  evoke  in  the  student  the 
constant  thought  of  Why  ?  together  with  the  love 
for  the  experiment.  The  course  extends  over  seven 
months  and  one-half,  in  three  lectures  a  week.  It 
is  supplemented  by  laboratory  work  of  eight  hours 
per  week  in  which  some  fifty-odd  experiments,  se- 
lected from  the  lecture  experiments,  are  performed 
by  the  student.  The  chemistry  of  the  metals  in 
conjunction  with  qualitative  analysis  comprises  the 
second  year's  work  of  equal  time-extension,  but  only 
two  lectures  a  week. 

The  illustrations  are  made  with  the  chief  aim  of 
engineering  simplicity.  Thanks  are  duly  given  to 
each  and  every  chemist  who  has  given  a  laborious 
life  in  contributions  with  which  to  build  up  the 
chemistry  of  to-day. 

THE  AUTHOR. 

HOUGHTON,  MICHIGAN,  November  15,  1905. 


CONTENTS. 


CHAPTEE  I. 

THE   NATURE   OF   AIR   AS   A    MIXTURE   OF   GASES. 

Introductory  remarks 1 

The  nature  of  air        .    -    -  3 

Deductions  ;  How  much  air  will  be  absorbed  by  a  given  weight 

of  copper  ? 5 

How  much  air  will  be  absorbed  frcm  a  given  volume  of  copper?  7 

Calibration  of  the  apparatus 8 

Deduction    .    .                        11 

Ozone  and  azote  ;  Weights  of  air,  nitrogen  and  ozone  ;  Sulfur  .  13 

Is  the  burning  of  sulfur  similar  to  the  scale-forming  of  copper?  14 

Use  of  litmus  ;  Acids  ;  Definition  of  an  oxyd 15 

General  deductions  ;  A  deoxydizing  substance,  carbon  ....  16 

Metals  and  non-metals 17 

CHAPTER  H. 

THE   NATURE   OF   WATER. 

The  ancient  version  of  things  ;  The  kinds  of  water 18 

Physical  properties  of  water 19 

Chemistry        21 

Action  of  steam  on  iron  and  zinc 22 

On  copper  ;  Keverse  proof 23 

Hydrogen  ;  Electrolysis 25 

Oxygen  ;  Deductions  ;  Inverse  proof  . 31 

Explanation  of  action  ;  Law  ;  Idea  of  an  atom 33 

Hydrogen  peroxyd 34 

CHAPTEE  III. 

GREEN    VITRIOL   OR   COPPERAS. 

Description 35 

Chemical  investigation  ;  Deduction 37 

(ix) 


X  CONTENTS. 

PAGE 

Presence  of  sulfur  established  ;  The  oil  of  vitriol .......  40 

Preparation  of  a  quantity  of  the  oil 41 

Investigation  of  the  oil 43 

A  different  oil 44 

Work  with  this  other  oil,  the  liquid  residue 45 

A  higher  oxyd  of  sulfur 46 

Action  of  the  liquid  residue  on  lead  and  silver    .        47 

Investigation  of  the  white  fumes  that  crystallized 49 

Summary  ;  Direct  proof  of  the  presence  of  water  in  the  liquid 

residue,  the  sulfuric  acid 50 

Proof  of  the  volume  composition  of  the  sulfur  oxyd,  SO2  ...  52 

The  dilution  of  sulfuric  acid 54 

Molecular  weight  ;  Hydrates  of  sulfuric  acid    .        55 

Action  of  sulfuric  hydrates  on  the  metals 56 

The  iron  vitriols. 58 

Preparation  of  sulfur  dioxyd 59 

Generation  of  hydrogen 61 

Koenig's  generator 62 

CHAPTER  IV. 

THE   LEPSON    OF    LIMESTONE. 

The  lime  minerals 64 

Action  of  heat  on  calcite 65 

Partial  proof  of  the  lime  gas 67 

Study  of  the  residue 70 

Formation  of  lime  hydroxyd 71 

Action  towards  acids .    .    .    .    , 72 

Action  of  the  lime  gas  upon  the  lime  hydroxyd  ...            .    .  73 

Deduction .    . 74 

Summary  of  the  limestone  lesson 75 

CHAPTER  V. 

THE   LESSON    OF   WOOD   ASHES. 

Wood  and  coal  ashes 76 

Potash  ;  Investigation  of  the  lye 77 

Potassium  hydroxyd 79 

Hydrates 80 

Proof  of  the  hydroxyd  nature  of  solid  caustic  potash 81 


CONTENTS.  XI 

PAGE 

Action  of  the  preceding  substances  on  the  vitriol  solutions    .    .  82 

Potassium                                .        .    . 84 

Physical  and  chemical  properties  of  potassium *   87 

Use  of  potassium  in  finding  the  non-metal  in  gas  from  limestone.  88 

Alkaline  substances 91 

CHAPTER  VI. 

THE   LESSON    OF   COMMON   SALT. 

Forms  of  natural  salt * 92 

Investigation .  93 

Work  with  the  salt  gas  .               94 

Chlorine      .                    ...                                                    .    .    .  98 

Preparation  of  chlorine.                                                       .        .    .  99 

Chemical  properties  of  chlorine 104 

Chlorate       .        ...                                       105 

Process  for  making  potassium  chlorate  ;  Composition  of  salt  gas.  106 

Properties  of  hydrogen  chlorid 107 

HC14-water .    .  108 

Advantages  of  different  driers Ill 

Acid  hydrometers 112 

The  discovery  of  the  metal  sodium,  by  working  with  the  salt 

cake             113 

Physical  and  chemical  properties  of  sodium 116 

Oxyds  of  sodium 118 

CHAPTER   VII. 

THE   STORY    OF   SODA   ASH    AND   LEBLANC. 

The  Leblanc  soda  process 119 

Sodium  carbonate  and  bicarbonate 121 

Caustic  soda  ;  Lye  balls  ;  Kelp 122 

CHAPTEK  VIII. 

ON    THEORIES,    COMBINING   WEIGHTS,    ATOMIC   WEIGHTS 
AND   VALENCES. 

A  uniform  system  of  writing  formulas 123 

The  idea  of  radicals .  124 

The  electrochemical  series  ;  Valence 12 


Xll  CONTENTS. 

PAGE 

The  atomic  weights  of  the  elements ;  Molecular  weights  and 

volume  weights .    .        - 126 

Hydroxyl  radical  ;  Sulfate  instead  of  vitriol 129 

Atomic  weights  of  calcium,  copper,  lead  and  zinc  ......  130 

Atomic  weights  of  silver  and  gold  .    .    . 131 

Relation  between  atomic  weights  and  specific  heats  of  the  ele- 
ments   132 

Law  of  Dulong  and  Petit ;  Review  of  the  action  of  chlorine  on 

the  alkaline  hydroxyds 133 

Dichloroxyd    ...                134 

Chlorates.    ...                135 

Oxygen  from  chlorates ....  136 

CHAPTER  IX. 

BROMINE,    IODINE,    FLUORINE. 

Bromine  from  the  mother  liquor  of  the  salt  works 137 

Compounds  and  actions  of  bromine ...  138 

Iodine 139 

Properties  of  iodine  ;  Starch  and  iodine 141 

Compounds  of  iodine 142 

General  remarks 143 

Ismorphous  substances  ;  Fluorine 144 

Flux 145 

Investigation  of  the  fluorite  gas 146 

Composition  of  the  gas 148 

The  etching  process 149 

The  nature  of  fluorine  ;  The  metal  in  fluorspar 150 

CHAPTER  X. 

LECTURE   ON    NITER   OR   SALTPETER. 

The  kinds  of  niter 152 

Solubility  ;  Investigation  of  the  soda  niter 153 

The  nature  of  nitrogen 154 

The  spirits  of  niter 155 

Aqua  regia 156 

The  properties  of  nitrogen 159 

Properties  and  composition  of  spirits  of  niter 160 

Nitrates ,  164 


CONTENTS.  Xlll 

PAGE 

Gunpowder 166 

Calculations  on  the  explosive  power  of  gunpowder 168 

Other  powders ;  Investigation  of  the  nitrous  fumes 170 

Nitrogen  dioxyd 171 

Nitrogen  monoxyd 176 

Proof  that  the  formula  is  NO 177 

Properties  of  NO 178 

The  ring  test  for  nitrates 178 

Nitrites .    .  179 

Preparation  of  KNO* .              180 

Dinitrogen  trioxyd 181 

Nitrite  test,  using  starch  and  iodine  compound  ;  Laughing  gas  .  182 

Properties  of  N2O 183 

Preparation  of  the  gas  on  a  large  scale 184 

Recapitulation  of  the  oxyds  of  nitrogen 185 

CHAPTER  XL 

AMMONIA,  A    VOLATILE  ALKALI.       A  COMPLEX  METALLIC  RADICAL. 

The  nascent  state ;  Ammonia.       186 

Investigation 187 

Preparation  of  ammonia 188 

Sal-ammoniac 189 

Composition  of  ammonia 190 

Proof  that  hydrogen  is  contained  in  ammonia 191 

Proof  that  ammonia  contains  no  oxygen  ;  Demonstration  that 

the  formula  is  NH3 192 

The  chemical  nature  of  ammonia 194 

Ammonium  ...        195 

Indirect  proof  of  the  ammonium  theory    .    : 196 

Formation  of  ammonium  compounds 197 

Liquid  ammonia 200 

Preparation  of  ammonia  water 201 

Carbonates       203 

Sal-ammoniac 204 

Soldering,  with  use  of  sal-ammoniac      .    -                205 

Solvay  process , 206 


XIV  CONTENTS. 

PAGE 

CHAPTER  XII. 

ORIGIN   AND   OCCURRENCE   OF   NITER. 

Sources  of  nitrogen .  209 

Niter  plantation 210 

The  Chili  niter  deposits 211 

The  origin  of  the  deposit 212 

Conversion  of  soda  niter  into  potash  niter 213 

CHAPTER  XIII. 

THE   MANUFACTURE    OF   HYDROGEN    SULFATE   OR    SULFURIC    ACID 
ON   A    COMMERCIAL  SCALE. 

Direct  proof  that  H2SO4  results  from  the  union  of  SO3  with  H2O  .  216 
Cost  of  the  sulfur-nitric  acid  method  ;  The  SO2-nitric  acid 

method 217 

The  lead  chamber  process. 218 

Sulfur  from  pyrite 219 

The  plant  needed 220 

The  Glover  tower 222 

Size  and  cost  of  plant .  224 

The  Gay-Lussac  tower 225 

The  Lunge-Rohrmann  plate  column 226 

Concentration  of  the  chamber  acid ......  227 

The  Gridley  system  ;  Lemaire  and  Co.' s  stills 228 

Loss  of  platinum;  Manufacture  of  oil  of  vitriol  by  Winkler's 

method .  t.  .  .  .  230 

The  direct  contact  method 231 

CHAPTER  XIV. 

OTHER  COMPOUNDS  OF  SULFUR. 

The  sulfid  ores 233 

Hydrogen  sulfid 234 

Proof  of  the  formula,  H2S 235 

Generation  of  H2S  in  a  steady  current  at  a  minimum  of  cost  .  236 

Properties  of  H2S ,237 

Action  of  H2S  on  KOH 239 

ActionofH28onNaOH;OnCa(HO)2 240 

Calcium  monosulfid 241 


CONTENTS.  XV 

PAGE 

Action  of  sulfur  on  the  alkaline  hydroxyds 242 

Sodium  hyposulfite  and  its  manufacture 243 

Test  for  thiosulfate 244 

Action  of  H'S  upon  solutions  of  metallic  salts 245 

Examination  of  the  precipitates  obtained      249 

Hydrogen  persulfid 253 

Sulfur  chlorid  and  carbon  disulfid 254 

CHAPTER  XV. 

CARBON  COMPOUNDS;   ORGANIC  BODIES. 

Native  carbon 257 

Coal 258 

Carbon  dioxyd 259 

Chemical  properties 260 

Composition  of  COS               261 

The  atomic  weight  of  carbon  ;  Carbon  monoxyd ,    .  262 

Proof  of  the  composition  of  CO 263 

Structure  of  plants .        .    .  264 

Experiments  with  cellulose 265 

The  formula  of  cellulose  derived  from  the  results  of  combustion.  266 

Parchment 270 

Xitro-cellulose,  gun-cotton 271 

Gun-cotton  as  an  explosive 272 

Destructive  distillation  of  wood 274 

Charcoal ;  Pyroligneous  acid 276 

Acetic  acid 278 

Wood  tar 279 

Carbolic  acid  ;  Picric  acid 282 

Paraffin ....  283 

Analysis  of  wood  gas 284 

Marsh  gas,  methane 294 

Safety  lamp 300 

The  theoretical  importance  of  marsh  gas  .        301 

The  marsh  gas  or  paraffin  series  of  hydro-carbons 302 

Propane  ;  Butane  ;  Isomerids 303 

Pentane    .    . 304 

Carbonyl-hydroxyl  ;  Wood  subjected  to  pressure  and  heat.  .    .  305 


XVI  CONTENTS. 


CHAPTER  XVI. 

MINERAL   COAL   AND   ITS   CHEMISTRY. 

The  kinds  of  coal 308 

Composition  of  coal 310 

Ultimate  composition 311 

Proximate  composition  ;  Origin  of  coals 312 

The  coking  process 316 

Coke 318 

Coal  tar  ;  Naphthaline  ;  Nitrobenzol .  320 

Anilin  ;  Complex  base  ;  Methylanilin 321 

Rosanilin  ;  Mauvanilin 322 

CHAPTER  XVII. 

THE  GASES  FROM  THE  DISTILLATION  OF  COAL  ;    THE  MANUFACTURE 
OF  ILLUMINATING  GAS  AND  GAS  COKE. 

The  qualitative  composition  of  the  coal  gas 324 

Dissociation  at  high  temperatures  ;  Plan  for  gas  works  ....  325 

The  dimensions  of  the  plant 329 

Water-gas 331 

Fuel-gas 333 

Rock-oil,  petroleum  .    .  335 

Chemical  properties  ;  Refining  of  the  crude  oil 336 

The  flash-point ;  Natural  gas  . 337 

CHAPTER  XVIII. 

THE  HOMOLOGUES  OF  CELLULOSE— STARCH,  DEXTRIN,  SUGARS. 

The  wheat  grain 339 

Starch 340 

Chemical  properties  of  starch  ;  Dextrin 341 

The  sugars  ;  Cane  sugar 342 

Grape  sugar 343 

Fruit  sugar 344 

Milk  sugar  ;  Gum  arabic 345 

CHAPTER  XIX. 

ALCOHOL,  SPIRITS  OF  WINE,  ETHYLHYDROXYD. 

The  production  of  alcohol 346 

Fermentation  ;  Yeast 347 


CONTENTS.  XV11 

PAGE 

The  manufacture  of  ethyl  alcohol 348 

Absolute  alcohol 349 

Properties  and  chemical  constitution  of  alcohol 350 

CHAPTER  XX. 

SOME  IMPORTANT  DERIVATIVES  OF  ALCOHOL. 

Ether,  ethyl  oxyd 352 

Chloroform .    .  353 

lodoform  ;  Aldehyde  ;  Chlopal    ...                354 

Mercuric  fulminate;  Preparation  of  the  fulminate 355 

Manufacture  of  percussion  caps 356 

Silver  fulminate 357 

CHAPTER  XXI. 

SOME  ORGANIC  ACIDS. 

Formic  acid  and  acetic  acid 358 

The  manufacture  of  vinegar 360 

Oxalic  acid 361 

Chemical  properties  ;  Methods  of  manufacture 363 

Lactic  acid  and  tartaric  acids 364 

Tartar  emetic          365 

Citric  acid  ;  Malic  and  tannic  acids '  366 

Ink 367 

Leather 368 

•Gallic  and  pyrogallic  acids 369 

CHAPTER  XXII. 

THE  VEGETABLE  FATS  AND  ANIMAL  FATS. 

Plant  oils 370 

Animal  fats 371 

Chemical  action  of  fats 372 

Glycerin 373 

Manufacture  of  glycerin 374 

Tri-nitro-glycerin  ;  Dynamite 875 

Manufacture  of  nitro-glycerin  ;  Tallow 376 

Soap ;  Drying  oils •    •    •    .  377 

Turpentine 378 

Rosin .379 


XV111  CONTENTS. 

PAGE 

Eubber 380 

Vulcanizing  of  rubber  ;  Ebonite.        . 382 

CHAPTER  XXIII. 

ORGANIC  ALKALOIDS. 

Theobromin  ;  Caffein  ;  Urea ;  Morphin 383 

Chinin  ;  Strychnin;   Brucin  and  Atropin 384 

Cocain  ;  Nicotin 385 

CHAPTER  XXIV. 

ALBUMEN  AND  ALBUMENOIDS 

Albumen 386 

Haemoglobin  ;  Haematin 387 

Fibrin ;  Casein  ;  Horn,  hair  and  skin 388 

Distillation  of  albumenoid  substances 389 

Neat's-foot  oil 390 

CHAPTER  XXV. 

ORIGIN  OF  CYAN  IDS. 

The  discovery  of  the  yellow  prussiate  of  potash 391 

Potassium  ferrocyanate 392 

Potassium  cyanid  and  its  preparation 393 

Chemically  pure  potassium  cyanid 394 

Hydrogen  cyanid  ;  Prussic  acid 395 

Preparation  of  prussic  acid  and  of  cyanogen ;  Composition  of 

cyanogen  ;  Sulfocyanogen  and  sulfocyanates 397 

Potassium  ferricyanate 398 

Potassium  cyanate ;  Cyanuric  acid 399 

Fulminic  acid 400 

CHAPTER  XXVI. 

BONE-ASH  AND  PHOSPHORUS. 

Bone-ash      401 

Experiments  on  the  bone-ash 402 

The  discovery  of  phosphorus "..._..  404 

The  modifications  of  phosphorus     ...        405 

Red  phosphorus 406 

Black  phosphorus ;  The  atomic  weight  of  phosphorus  ;   Phos- 
phorus pentoxyd 407 


CONTENTS.  XIX 

PAGE 

Preparation  of  phosphorus  pentoxyd  ;  Orthophosphoric  acid.  .  408 

Preparation  of  the  ortho-acid  ;  Orthophosphates 409 

Microcosmic  salt.    .    -  410 

Insoluble  orthophosphates ;  Molybdate  test 411 

Pyro-  and  metaphosphoric  acids  and  their  preparation  ....  412 

Phosphorus  trioxyd  ;  Phosphorous  acid 413 

Hypophosphorous  acid  ;  Phosphorus  trichlorid  ....  .  414 

Phosphorus  pentachlorid  ;  Phosphine 415 

Preparation  of  phosphine •    •  416 

Composition  of  phosphine ;  Phosphonium 417 

Liquid  hydrogen  phosphid ;  Metallic  phosphids 418 

APPENDIX. 

The  chemical  elements,  their  symbols,  equivalents,  and  specific 
gravities 419 

Table  for  the  comparison  of  the  scales  of  Reaumur's,  Celsius's, 
and  Fahrenheit's  thermometers 421 

Rules  for  the  conversion  of  the  different  thermometer  degrees 
into  each  other 422 

Table  of  the  liter  weights  of  gases 423 

INDEX  .  .    425 


\ 


Of    THE 

ERSITY 

OF 
•  IFQR1 


CHEMISTRY   SIMPLIFIED. 


CHAPTER  I. 

THE  NATURE  OF  AIR  AS  A  MIXTURE  OF  GASES. 

INTRODUCTORY  REMARKS.     I  show  you  this  small 
copper  ingot.     It  was  made  by  pouring  liquid  cop- 
per, at  a  yellow  heat,  into  an   iron  mould.     You 
notice  a  bright  red  color  on  the  sides  and  bottom,  a 
dark  reddish-gray  on  the  upper  side,  and  a  pale 
yellowish-pink  on  this  spot  which  I  scrape  with  the 
knife.     By  drilling  a  hole  through  the  ingot,  or  by 
sawing  it  into  two  we  find  the  pale,  soft  yellow- 
ish-pink color  persistent  throughout   the   interior. 
Hence  we  infer  that  the  yellowish-pink  is  the  true 
color  of  copper,  while  the  red  and  gray-red  at  the 
outside  must  be  due  to  a  change  which  happened 
to  the  ingot  during  the  time  when  it  passed  from 
yellow  heat  to  the  temperature  of  the  room.     If  we 
do  not  take  this  change  as  a  simple  matter  of  fact, 
but  if  instead  we  ask  for  the  reason  of  the  change, 
then  our  mind  is  scientific,  it  is  above  the  average, 
and  there  is  hope  for  us.     Now  there  are  two  ways 
for  satisfying  this  desire  for  the  reason  for  things. 
Along  one  way  we  just  ask  the  nearest  man  or  the 
handiest  book,  along  the  other  way  we  set  to  work 
it  out  ourselves.     Following  the  second  and  much 
harder  road,  we  become  investigators  and  inventors. 


2  CHP;MISTRY  SIMPLIFIED. 

You  have  come  here  to  learn  chemistry,  and  my 
duty  is  to  show  you  the  way.  I  may  lead  you 
along  the  first  trail  by  means  of  a  book  and  recita- 
tions and  my  own  acquired  knowledge  of  the  nature 
of  things.  However,  I  choose  to  take  you  by  the 
second  trail,  difficult  in  steep  slopes  and  rapid 
descents,  but  which  will  ultimately  take  you,  when 
the  pass  shall  have  been  won,  into  the  beautiful 
valley  of  intellectual  satisfaction  and  fruitful  tech- 
nical invention.  Some  may  get  exhausted  on  the 
journey,  and  some  may  not  have  the  right  eyes  to 
see,  the  right  hands  to  grapple  with  the  difficulties ; 
for  them  of  course  there  is  no  hope  and  they  must 
take  the  other  trail,  they  will  not  become  leaders  in 
the  profession.  Those  who  are  born  with  right 
desire  will  ultimately  get  to  the  goal  by  any  road 
whatsoever ;  but  they  will  have  spent  much  time, 
much  energy,  in  doing  useless  things.  My  object,  as 
your  teacher,  is  to  point  out  things  to  you  so  that  you  may 
save  the  waste  and  arrive  much  more  rapidly  at  the  pass. 

Let  us  return  to  our  ingot  and  ask  :  What  causes 
the  copper  to  be  of  different  colors  on  the  outside 
from  the  inside  ?  This  question  we  name,  by  gen- 
eral consent,  a  chemical  question  because  the  change 
which  happened  to  the  outside  of  the  ingot  is  a  per- 
manent change,  by  which  the  substance  has  acquired 
different  properties  throughout.  If  I  bend  this  wire 
there  is  also  a  permanent  change,  but  it  is  only  a 
change  of  shape,  the  copper  itself  has  not  changed 
any  of  its  properties.  If  we  inquire  about  this 
change  of  form  in  the  new  positions  of  the  copper 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES. 

particles,  we  have  to  deal  with  a  proposition  in 
physics.  There  are,  of  course,  many  changes  in 
which  physics  and  chemistry  overlap,  when  we  must 
enter  into  both  sciences.  It  is  merely  a  matter  of 
convenience,  for  the  sake  of  more  effective  work 
that  this  division  into  physics  and  chemistry  has 
been  made.  One  set  of  men  pursue  the  one  set  of 
phenomena,  becoming  more  expert  in  observation 
than  if  they  spread  themselves  over  both  sets. 

1.   The  nature  of  air. 

Pursuing  the  question  concerning  the  changes  at 
the  surface  of  the  copper  ingot,  we  shall  now  insti- 
tute experiments,  every  one  of  which  will  give  rise 
to  new  questions. 

In  Figs.  1,  2,  3,  4  the  trial  arrangements  are  set 
up  to  meet  those  questions. 

In  Fig.  1,  a  bright  piece  of  sheet  copper  A  is 
placed  within  the  non-luminous  or  purplish  part  of 
the  flame  F.  It  is  evident  that  here  the  metal  will 
be  exposed  to  the  action  of  heat,  to  the  action  of  air 
and  to  the  action  of  the  substance  of  the  flame. 
The  metal  at  bright  red  heat,  under  these  condi- 
tions covers  itself  with  a  dark  scale,  which  peels  off 
and  is  found  to  be  very  brittle.  In  Fig.  2,  the  metal 
A  is  within  the  hard-glass  tube  T,  which  is  closed 
at  one  end,  open  at  the  other  end.  The  substance 
of  the  flame  does  not  come  in  contact  with  the  metal, 
but  the  heat  of  the  flame  is  conducted  through  the 
glass,  the  metal  becomes  red  hot  and  covers  itself 
with  a  very  thin  film.  Here  the  air  has  access,  but 


4  CHEMISTRY    SIMPLIFIED. 

limited.  Fig.  3,  shows  the  metal  strip  A  within  a 
tube  T.  The  tube  was  then  drawn  out  at  (7,  leaving 
a  narrow  neck,  was  then  connected  with  an  air 
pump  until  all  air  was  drawn  out,  when  the  neck 
C  was  allowed  to  close  up  by  means  of  a  sharp,  hot 
flame  (blow-pipe  flame).  If  then  the  tube  T  be 


FIG.  l. 
A 


FIG.  2. 


made  red  hot  in  the  flame  jP  and  kept  so  for  any 
length  of  time,  we  find,  on  cooling,  that  no  change 
has  taken  place,  the  copper  is  bright  with  its  fine 
pale  yellowish-pink  color.  Lastly  in  Fig.  4,  we  have 
the  copper  strip  in  a  glass  tube  which  is  open  at 
both  ends.  Owing  to  inclined  position  a  lively  air 
current  will  set  in  in  the  direction  of  the  arrows  as 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.          O 

soon  as  the  tube  is  heated  by  the  flaine.  We  find 
quickly  that  the  last  conditions  produce  the  most 
change  on  the  copper — the  most  rapid  development 
of  the  scale. 

Deduction  from  the  four  experiments:  1.  Copper 
takes  from  the  air,  at  red  heat,  a  portion  of  the  air 
and  changes  to  a  brittle  scale.  2.  The  substance  of 
the  flame  does  not  enter  into  this  change,  only  the 
heat  of  the  flame.  Two  questions  now  suggest 
themselves :  1.  How  much  will  be  absorbed  by  a 
given  weight  of  copper?  2.  How  much  of  a  given 

FIG.  5. 


_L_L 


volume  of  air  will  be  absorbed  ?  In  order  to  an- 
swer the  first  question  rig  an  apparatus  as  shown 
in  Fig.  5,  where  T  is  an  infusible  glass  tube  (so- 
called  combustion  tube)  not  less  than  J"  inside 
diameter.  The  tube  is  bent  over  the  blast  lamp. 
Place  the  tube  in  a  horizontal  position  by  means  of 
clamp-stand  5.  Select  a  porcelain  boat  sufficiently 
narrow  to  pass  into  the  tube  easily.  Clean  and 
weigh  the  boat.  We  choose  glazed  porcelain 
because  it  will  not  become  soft  except  at  white  heat, 
because  it  does  not  change  in  weight  when  heated 


6  CHEMISTRY    SIMPLIFIED. 

in  air.  Place  into  this  boat  about  0.100  grain  of 
copper  filings,  that  is  to  say  you  must  take  the 
weight  very  accurately.  But  it  does  not  matter 
whether  you  take  0.095  or  0.102,  only  by  taking 
0.100  accurately  you  will  save  figuring  the  percent- 
age. You  are  told  to  take  filings,  because  in  this 
form,  the  metal  will  be  exposed  with  a  maximum 
of  surface  and  a  minimum  volume,  which  is  most 
desirable,  since  the  intended  action  proceeds  from 
the  surface.  Shove  the  boat  into  the  tube  as  shown 
in  the  figure,  and  place  the  lamp  so  that  the  entire 
length  of  the  boat  can  be  brought  to  redness.  The 
bent  part  of  the  tube  being  bent  upwards,  a  so-called 
draught  will  arise  as  by  a  chimney,  because  a  col- 
umn of  hot  air  being  in  the  vertical  tube,  this  hot 
air  being  lighter  than  the  cold  outer  air,  the  latter 
will  pass  in  at  the  lower  end  and  push  out  the  warm 
air,  hence  a  steady  air  current  will  pass  through  the 
tube  in  the  direction  of  the  arrow's  pointing.  Allow 
this  action  to  proceed  for  30  minutes.  Do  not  for- 
get to  place  a  few  fibres  of  infusible  asbestus  between 
the  tube  and  the  boat,  for  the  tube  may  become 
soft  and  cause  the  boat  to  stick.  Should  the  tube 
exhibit  a  tendency  to  sag  you  will  prop  it  up  at  the 
end  by  means  of  a  piece  of  brick.  Remove  the 
flame  at  the  expiration  of  the  half  hour,  let  the  tube 
cool  down  until  it  can  be  held  in  the  hand.'  Pull 
out  the  boat  and  weigh.  Return  the  boat  to  the 
tube,  replace  the  lamps  and  work  for  another  half 
hour.  Then  weigh  again.  If  the  second  weight  is 
not  equal  to  the  first,  you  cannot  be  certain  that  the 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.          7 

copper  has  saturated  itself,  and  a  third  period  of 
heating  becomes  necessary,  and  perhaps  a  fourth 
until  you  get  constant  weight.  Many  trials,  made 
with  greatest  care,  show  that  0.100  copper  will  in- 

FIG.  6. 


crease  to  0.1254  and  no  further,  and  thus  the  result- 
ing dark  gray-black  product  of  change  will  contain 
in  100 :  Copper  79.6  and  air  20.4. 

2.  How  much  will  be  absorbed  from  a  given  volume 
of  air  f 

For  an  answer  to  this  question  let  an  apparatus 


8  CHEMISTRY    SIMPLIFIED. 

be  rigged  as  in  Fig.  6.  We  must  make  provision 
to  pass  and  repass  the  same  volume  of  air  over  the 
heated  copper  without  any  air  coming  from  the 
outside,  nor  any  air  escaping  to  the  outside.  Let 
T  again  be  of  hard  glass  i  or  -^  inch  internal  diam- 
eter and  5  inches  long.  Introduce  a  roll  of  fine 
copper  gauze,  5,  then  bend  the  tube  into  a  double  L. 
Paste  on  a  mark  at  M.  Determine  or  gauge  the 
volume  of  the  tube  by  filling  it  with  mercury  up  to 
the  mark  M,  and  then  weigh  the  mercury.  If  the 
weight  of  the  mercury  be  g,  then  g  1 13.6  =  F(in  cubic 
centimeters).  Provide  two  soft  glass  tubes,  S,  &', 
with  stoppers,  the  upper  ones  to  receive  the  tube  T, 
the  lower  ones  to  receive  narrow  glass  tubes,  which 
are  connected  by  rubber  tubing,  2,  h  with  the  glass 
syphons  1,  3.  These  stand  in  beaker  glasses,  R,  R'. 
Calibrate  the  tube  S  into  cubic  centimeters,  the 
lower  side  of  the  upper  stopper  forming  the  0  mark. 
Calibration.  Stand  8  upside  down,  after  a  solid 
stopper  1,  Fig.  7,  has  been  pushed  into  the  0  mark. 
Then  weigh  out  (to  0.1  gram)  5  X  13.6  =  68.0  grams 
of  mercury  and  pour  this  into  the  tube.  Make  a 
scratch  (with  a  glazier's  diamond,  with  a  sharp 
splinter  of  quartz,  or  with  a  hard  file)  tangent  to 
the  meniscus.  Measure  the  distance  from  0  to  5 
with  a  scale  or  pair  of  dividers.  Lay  this  distance 
down  a  strip  of  white  paper  and  divide  into  5  equal 
parts.  Lay  on  these  divisions  beyond  five  for  the 
whole  length  of  the  tube.  Then  paste  the  strip 
upon  the  tube  so  that  the  0  marks  fall  together, 
and  then  cover  the  paper  on  the  outside  with  molten 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.          VJ 

paraffin.  Thus  your  tube  is  calibrated  into  cubic 
centimeters.  Weighing  out  a  defined  quantity  of 
mercury  is  not  quite  so  easy  as  it  sounds.  Proceed 
as  follows :  Place  a  very  small  beaker  glass  upon 
a  so-called  pulp  balance  (it  were  foolish  to  use  a 
fine  balance  because  we  only  want  to  weigh  as  close 
as  0.1  gram).  Why  ?  Because  0.1  gram  of  mer- 


cury corresponds  to  less  than  0.01  cubic  cent.,  and 
we  do  not  care  to  read  a  volume  closer  than  0.1 
cubic  cent.  It  would  in  fact  be  quite  sufficient 
accuracy  if  we  got  any  weight  of  mercury  within 
1.0  gram.  Make  a  pipette  with  capillary  outlet  by 
drawing  out  an  8"  x  J"  soft  glass  tube  over  the 
lamp  flame  as  shown  in  Fig.  8,  and  cut  off  with  file 
at  point  a.  Fill  this  tube — by  sucking — with  mer- 
cur\T,  and  let  this  latter  flow  into  the  beaker,  until 
the  balance  tips.  The  beaker  has  been  previously 
balanced  by  shot,  and  the  required  weight,  68  grs., 
has  been  placed  upon  the  weights'  pan.  The  first 
finger  closes  the  upper  end  of  the  tube  at  the 
moment  of  tipping.  After  the  apparatus  (Fig.  6) 


10  CHEMISTRY    SIMPLIFIED. 

has  been  set  up — the  tubes  S,  S'  being  held  in 
place  by  clamp-stands  or  tripods  or  under  prop- 
pings— the  beaker  glasses  R,  R'  are  filled  with 
water,  the  syphons  1,  3  are  filled  by  sucking  at 
the  end  of  the  detached  rubber  tubing  until  the 
water  comes  to  the  mouth,  the  rubber  being  then 
joined  to  the  tubes  S,  S'.  R'  is  then  raised  upon 


blocks  until  the  water  reaches  the  mark  M,  while 
R  is  lowered  until  its  water  level  falls  together 
with  a  division  of  the  scale  on  S,  say  for  in- 
stance 10.  We  are  having  then  a  volume  of  air  V 
equal  to  10  plus  v  (v  being  volume  of  tube  T). 
Let  v  be  5  c.c.  for  example ;  then  the  total  volume 
will  be  10  pins  5  equal  15  c.c.  Bring  now  the 
burner  B  under  T  so  that  the  copper  gauze  5  be- 
comes red  hot.  Cause  the  air  to  move  slowly  over 
the  hot  copper,  by  lowering  beaker  R  and  raising 
R  at  the  same  time.  Repeat  this  movement  10 
times.  Then  remove  the  burner  and  let  the  tube 
T  return  to  the  temperature  of  the  room.  Bring 
the  water  to  the  mark  M  and  adjust  R  in  such  a 
way  that  its  water-line  and  the  water-line  in  S  fall 
into  one  level.  On  reading  off  the  position  of  the 
water-line  8  on  the  scale,  we  will  read  7,  that  is, 
3  c.c.  of  air  have  disappeared  ;  15  c.c.  of  air  have 
lost  3  c.c.,  5  c.c,  have  lost  1  c,c.  Bring  the  flame 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.       11 

back  and  again  pass  10  times  over  the  hot  copper. 
On  cooling  will  find  the  same  result  as  before ; 
hence  the  loss  of  the  air,  under  these  conditions,  is 
constant. 

Deduction.  Air  is  composed  of  at  least  two  parts, 
which  possess  each  decidedly  different  properties,  or 
in  other  words :  Air  consists  of  two  different  gases. 
Now  it  is  well  known  that  men  and  animals  must 
have  air  to  breathe.  Query?  Which  one  of  the 
two  gases  do  they  require,  or  do  they  need  both? 
As  the  one  gas  has  disappeared  into  the  copper,  we 
shall  have  to  experiment  with  the  £  residuum.  Let 
a  glass  jar  J,  Fig.  9,  be  filled  with  the  gas.  How  ?  A 
two-foot  length  of  }"  gas  pipe  2  (Fig.  10),  is  charged 


FIG.  9. 


FIG.  10. 


with  copper  gauze,  and  placed  in  a  charcoal  fur- 
nace 4-  Rubber  tube  5  leads  to  bottle  6  through  a 
two-hole  stopper ;  so  that  the  funnel  stem  7  may  pass 
through  second  hole.  If  water  be  poured  into  the 
funnel  the  air  will  be  driven  through  the  heated 
copper,  and  the  -J-  residuum  will  pass  through  1 
into  the  inverted  and  water-filled  jar  /  whose  open 
end  is  supported  under  water  by  metal  blocks  in 
the  basin  B.  We  will  now  do  a  little  figuring.  We 


12  CHEMISTRY    SIMPLIFIED. 

found  above  that  1  gram  of  copper  can  absorb  0.25 
gram  of  air.  One  litre  equals  1000  c.c.  of  air  and 
weighs  1.2932  gram,  hence  -J-  of  this  weight  is  0.258, 
that  is  one  single  gram  of  copper  is  sufficient  to 
take  the  absorbable  gas  from  one  litre  or  one  quart 
of  air.  50  grams  of  copper  will  furnish  (50x4)/5 
equal  40  litres  of  the  gas  we  desire.  But  for  our 
experiment,  that  is  to  fill  the  jar,  we  will  not  need 
more  than  one  or  at  the  most  two  litres  supposing 
that  the  whole  of  the  water  has  been  displaced  in  J 
so  that  the  bubbles  will  come  on  the  outside.  We 
remove  first  the  tube  1,  then  the  supporting  blocks 
and  push  a  flat  glass  plate  under  the  water,  and 
press  it  with  the  hand  against  the  jar  rim,  lift  the 
jar  out  and  stand  it  bottom  down  on  the  table  as  in 
Fig.  9.  A  mouse  having  been  trapped,  we  drop  the 
animal  from  the  trap  into  the  jar  and  replace  the 
glass  cover  plate.  At  once  the  mouse  shows  dis- 
tress, tumbles  into  a  heap,  and  after  a  few  spasmodic 
kicks  lies  quiet  and  is  dead.  Hence  we  draw  the  con- 
clusion that  the  part  of  the  air  which  is  absorbed 
by  the  copper,  is  the  part  also  which  sustains  animal 
life.  If  we  introduce  a  burning  taper  into  the  jar 
it  will  become  at  once  extinguished,  and  hence  it 
follows  with  some  considerable  probability  that 
breathing,  burning  and  scale  forming  of  copper  are 
similar  processes,  being  in  fact,  fundamentally,  the 
same  phenomenon. 

It  will  be  necessary,  for  clearness  and  conciseness 
of  expression,  to  distinguish  from  now  on  these  two 
parts  of  the  air  by  separate  names.  Properly  we 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.       13 

should  say — in  English — life-air  and  death-air; 
instead  Greek  words  are  chosen  by  scientists.  Life 
air  equals  ozone  ;  death  air  equals  azote.  The  root 
of  both  words  is  Zoe  equals  life  (zoology  equals  the 
science  of  living  things).  Ozone  equals  intense  life  ; 
azote  equals  no  life.  German  chemists  made  and 
use  the  term,  stickstoff  equal  to  suffocating  stuff;  the 
French  hold  on  to  azote,  English  and  Americans 
now  use  the  word  nitrogen  which  equals  niter-pro- 
ducer 

Weight  of  one  c.c.  of  nitrogen  equals  0.001256 
gram  (Regnault). 

Weight  of  one  c.c.  of  air  equals  0.001293  gram. 

Hence  it  follows  that  ozone  must  be  heavier  than 
air.  The  weight  of  ozone  follows  by  calculation. 

We  reduce  azote  to  terms  of  air  by  dividing  the 
weight  of  air  into  that  of  azote,  0.001256/0.001293 
equals  0.97137  which  equals  the  specific  weight  of 
azote  or  its  specific  gravity,  then  we  have 

4/<A9713  +  !    =1;    x  =(1-0. 777)5  =  1.1 145, 
o  o 

the  specific  gravity  of  ozone,  and  1.1145  X  1  -293  = 
1.441,  the  weight  of  1000  c.c.  of  ozone,  and  0.00144, 
the  weight  of  one  c.c.  of  ozone. 

Among  the  substances  more  or  less  familiar  to 
every  one  of  us  is  sulfur,  which  I  show  you  now  as 
crystal  and  massive  as  a  broken  lump.  Light  yel- 
low color  and  translucency  distinguish  it  from  other 
bodies.  If  washed  in  water  first,  it  yields  no  taste, 
it  is  insoluble  in  water.  Against  heat  it  is  quite 


14 


CHEMISTRY    SIMPLIFIED. 


susceptible.  I  place  some  of  it  upon  this  porcelain 
crucible  lid  and  put  the  flame  underneath.  We  see 
it  melt  quickly  into  a  dark  red-brown  liquid,  and 
then  vaporize.  Shortly  after  a  blue  flame  appears 
and  a  strong,  pungent  odor  permeates  the  air.  The 
sulfur  disappears  slowly.  Queries.  1.  Is  this  phe- 
nomenon similar  to  that  of  the  scale  forming  of 
copper,  to  the  burning  of  the  taper,  to  the  breath- 
ing? Has  either  the  ozone  or  the  azote  part  in  the 
disappearance?  Let  the  flask  1  be  filled  with  air 
and  a  few  c.c.  of  water  as  shown  in  Fig.  11.  Take 


a  strong  iron  wire  2,  hammer  it  flat  at  one  end  and 
rivet  it  to  a  small  iron  dish  3.  Put  sulfur  into  the 
dish,  heat  the  latter  over  a  flame  until  the  blue 
flame  is  strong,  then  lower  the  dish  into  the  flask 
until  the  plate  covers  the  mouth  of  the  flask.  The 
sulfur  keeps  on  burning.  Soon  a  white  cloud  ob- 
scures the  flame.  After  some  minutes  we  remove 
the  spoon  and  notice  that  it  begins  to  burn  when  it 
reaches  the  outer  air.  (Why?  Because  it  again 
finds  the  ozone,  which  had  become  used  up  in  the 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.       15 

flask.)  We  now  shake  the  water  and  the  gases 
together  in  the  flask  and  pour  out  the  water.  It  is 
somewhat  turbid  or  milky  ;  after  filtering  it  is  clear, 
it  has  a  sour  taste  and  changes  the  purplish  color  of 
litmus  to  bright  onion  red.  Litmus  is  obtained  by 
extracting  a  lichen  named  by  botanists  Roccella 
tindoria.  The  collected  lichen  is  allowed  to  fer- 
ment in  heaps,  is  then  torn  by  a  machine  and  al- 
lowed to  stand  with  water,  which  assumes  a  deep 
purplish  color;  is  used  as  a  dye  stuff  under  the 
name  of  orseille.  Now  vinegar  has  the  same  action, 
i.  e.,  a  sour  taste  and  turns  litmus  red.  Vinegar 
(from  French  viu-aigre  equal  wine  sour)  arises  when 
the  sugary  juice  of  grape  or  any  other  fruit,  is  al- 
lowed to  stand  in  a  warm  place. 

Wine  results  in  a  cool  place.  (Details  will  be 
given  later.)  The  Latin  name  for  vinegar  is  aridum, 
hence  it  came  that  later  on  all  sour  substances  were 
and  are  called  acids  in  English,  French,  Spanish, 
Italian;  but  in  German  the  word  satire  =  a  sour- 
ness, and  in  Swedish  syra,  only  differing  in  the 
vowel. 

When  Lavoisier,  in  1781,  had  observed  the  above 
phenomena,  he  proposed  the  name  oxyg^ne  in 
French,  oxygen  in  English  for  what  we  have  named 
ozone  or  life-air.  The  word  oxygen  is  derived  from 
the  two  Greek  words  oxus  =  sour,  sharp,  biting  and 
genomein  =  to  produce,  to  generate.  This  name 
we  shall  use  in  the  future. 

Definition:  The  combination  of  oxygen  with  a 
metal  or  non-metal  is  hereafter  to  be  designated  an 


16  CHEMISTRY    SIMPLIFIED. 

oxyd — oxid — oxide.  The  first  spelling  is  the  gram- 
matically more  correct,  but  the  last  spelling  oxide 
is  at  present  mostly  used  by  English  and  American 
chemists.  I  myself  use  oxyd — the  derivation  is 
from  oxydatus  =  oxydized. 

Hence  copper  scale  is  now  copper  oxyd,  the  pene- 
trating gas  from  burning  sulfur  is  sulfur  oxyd. 

General  deductions.  Air  being  a  compound  of 
azote  -f  oxygen  and  copper  oxyd  of  copper  -f-  oxy- 
gen, they  both  seem  to  be  representatives  of  the 
same  type  of  bodies  i.  e.,  compounds.  Whether  all 
compounds  are  of  one  kind  or  not,  we  cannot,  at 
this  stage  demonstrate.  The  term  compound  re- 
quires single,  or  simple  as  opposite.  We  will  define 
as  simple  bodies  or  elements  all  those  bodies  which 
can  be  brought  back  from  their  compounds  to  their 
first  condition  i.  e.,  with  all  their  previous  physical 
properties.  This  definition  is  raised  in  our  minds 
by  the  behavior  of  copper  oxyd  when  heated  in  a 
closed  tube  with  splinters  of  charcoal.  At  a  red 
heat,  the  scale  of  copper  oxyd  becomes  yellowish- 
pinkish.  On  cooling  a  spongy  mass  of  the  metal  is 
seen,  and  the  metal  possesses  all  previous  proper- 
ties. Hence  copper  is  a  simple  body  or  element. 
The  question  arises :  Are  all  our  well-known  metals 
elements?  Experiment  on  the  same  line  as  that 
with  the  copper,  answers  the  query  in  the  affirma- 
tive, though  there  will  be  found  experimental  diffi- 
culties with  some.  When  zinc  has  been  burnt  in 
air,  at  high  heat,  into  white  zincoxyd,  and  when  we 
heat  this  oxyd  with  charcoal,  we  will  get  no  satis- 


NATURE    OF    AIR    AS    A    MIXTURE    OF    GASES.       17 

faction  because  the  zinc  only  gives  up  its  oxygen  to 
the  coal  at  a  white  heat  which  the  glass  tube  cannot 
stand  ;  and  moreover,  at  this  high  temperature  zinc 
itself  is  a  vapor.  Special  arrangements  must  be 
made  in  this  case  to  catch  the  zinc  vapors,  which 
will  first  condense  to  a  liquid  and  the  latter  will 
solidify  into  metal  with  all  previous  properties. 
Though  we  know  as  yet  nothing  of  the  nature  of 
charcoal,  we  must  surmise  that  it  contains  a  body 
which  has  a  stronger  attraction  or  affinity  for  oxy- 
gen, at  high  heat,  than  the  metal.  Owing  to  this 
we  designate  charcoal  as  an  deoxydizing  substance, 
and  the  process  itself  we  call  deoxydation. 

Copperoxyd  -f-  charcoal  -f-  red  heat  =  deoxyda- 
tion. That  the  charcoal  forms  a  new  oxyd  during 
this  action  we  surmise  at  once.  Because  we  see  no 
deposit  of  any  kind  on  the  charcoal  or  on  the  tube, 
we  infer  that  this  new  oxyd  is  a  gas  at  the  ordinary 
temperature  of  the  air.  By  using  only  the  first  let- 
ters as  symbols,  we  can  represent  the  processes  thus  : 

Cu  -f  0  +  red  heat  —  CuO  —  oxydation. 

CuO  +  C  (charcoal)  +  red  heat  =  Cu  +  CO  =  de- 
oxydation. 

Sulfur  oxyd  can  be  decomposed  by  passing  it  in 
a  glass  tube  over  heated  charcoal.  Sulfur  will  de- 
posit in  the  tube ;  hence  sulfur  is  an  element,  ac- 
cording to  our  definition.  Yet  sulfur  is  not  at  all 
like  the  metals.  As  mentioned  above,  it  is  trans- 
parent and  very  brittle,  melts  at  a  very  low  heat 
and  becomes  a  vapor  at  250°  C.  Hence  we  at  once 
make  two  classes  of  elements:  metallic  elements: 
copper,  tin,  lead,  iron,  and  so  forth  ;  non-metallic 
elements :  sulfur,  oxygen,  azote,  etc. 
2 


CHAPTER  II. 

THE  NATURE  OF  WATER. 

To  us  who  are  dwelling  on  the  shores  of  a  great 
lake,  or  to  the  inhabitants  of  the  seashore,  the  idea 
must  early  present  itself  that  water  must  be  of  much 
importance  in  the  household  of  our  planet,  but  even 
to  him,  the  savage,  or  half  savage,  who  uses  water 
merely  to  quench  his  thirst,  water  must  be  an  ob- 
ject of  veneration  ;  and  the  inquisitiveness  of  the 
human  mind  must  bring  forth  even  in  him  a  desire 
to  learn  more  about  it.  The  ancient  thinkers,  with- 
out experiments,  said  water  is  one  of  the  primary, 
elementary  things,  and  together  with  air,  fire  and 
earth,  constitutes  the  great  Quartette  out  of  which 
comes  the  harmony  or  disharmony  of  all  things. 
Man's  body  is  made  of  earth  and  water,  his  soul  of 
air  and  fire,  thus  combining  within  himself  the  four- 
primary  things.  The  elementary  nature  of  water 
was  undoubted  up  to  the  end  of  the  18th  century. 
The  traveler  becomes  acquainted  with  good  water 
and  bad  water ;  water  which  has  a  bitter  taste,  an 
astringent  taste,  a  salt}7  taste,  a  nauseous  taste.  He 
learns  to  distinguish  between  Spring  water,  River 
water,  Swamp  water,  Sea  water.  It  was  early  ob- 
served that  water  combines  with  fire,  and  thus  pro- 
duces the  scalding  steam  which  would  lift  the  cover 
off  a  pot. 

(18) 


THE    NATURE    OF    WATER.  19 

Water  becomes  a  solid,  transparent  block  under 
the  influence  and  sway  of  chilling  Boreas,  the 
Xorthwind.  To  this  splendid  and  fleeting  thing 
the  Greeks  gave  the  name  Krystallos,  sometimes 
Kryos,  and  thus  became  the  founders  of  Orystal- 
lography,  because  when  they  found  the  beautiful 
transparent  Rockcrystal,  which  we  now  call  Quartz, 
they  considered  it  as  a  sort  of  permanent  ice,  and 
also  called  it  Krystallos.  Thus  the  name  was  ap- 
plied much  later  to  all  bodies  which  exhibit  geo- 
metrical outlines.  Remember  this  connection  be- 
tween ice  and  crystal.  More  wonderful  seemed  the 
snow,  and  it  took  much  hard  thinking  and  much 
controversy  until  snow  was  admitted  to  be  merely 
frozen  rain.  You  throw  your  snowballs  and  skate 
over  the  ice  and  never  once  think  anything  at  all, 
except  that  it  is  a  part  of  Winter's  fun,  and  yet  for 
a  hundred  years  men  have  been  studying  the  form 
of  snow-flakes,  and  each  one  found  something  new. 

Physical  properties  of  water.  Reference  is  here 
made  only  to  so-called  distilled  water,  that  is,  water 
which  has  been  in  the  form  of  steam  at  least  twice, 
and  which  has  only  been  kept  in  porcelain  crocks. 
All  other  water  is  impure  in  differing  degrees. 

Water  is  a  liquid  between  the  temperature  of  0° 
and  100°  C.  Below  0°  C.  it  is  solid— ice— brittle, 
and  yet  to  some  extent  plastic,  that  is,  capable  of 
deformation  under  strong,  slow  pressure.  (Bending 
of  glaciers  when  plowing  over  undulating  rocks.) 
Ice  is  colorless  in  small  pieces,  in  great  masses  it 
shows  a  green  or  sometimes  a  deep  blue  color. 


20  CHEMISTRY    SIMPLIFIED. 

Water  is  without  taste  (distilled,  water) ;  hence 
not  pleasant  to  the  palate.  It  is  without  color  when 
seen  in  a  bottle,  flask  or  jar;  but  when  looking 
through  a  long  column  it  becomes  more  and  more 
blue,  that  is,  all  but  the  blue  part  of  the  sunlight 
becomes  absorbed.  The  finest  effect  is  seen  off  the 
Savoy  shore  on  the  Lake  of  Geneva  (Switzerland), 
where  the  rocks  fall  abruptly  into  the  water  to  a 
depth  of  980  feet.  The  ocean  looks  blue-black,  but 
this  is  not  water  which  can  be  compared  to  distilled 
water,  whereas  the  water  of  the  Geneva  Lake  is  re- 
markably pure,  having  a  steady  and  strong  outflow 
in  the  Rhone  River. 

A  litre  of  water  at  -f-  4°  C.  weighs  sensibly  more 
than  at  0°  C.,  hence  ice  will  float  on  water.  If, 
however,  the  temperature  of  water  is  raised  by  heat- 
ing it  will  loose  in  density  and  soon  the  block  of  ice 
will  sink  to  the  bottom. 

Water  dissolves  all  solids,  some  very  slightly, 
others  in  large  quantities.  Note  this  very  import- 
ant property.  The  purer  the  water  the  more  ener- 
getic is  the  solving  action.  It  attacks  and  slowly 
dissolves  ordinary  glass,  but  porcelain  very  much 
less,  and  platinum  and  gold  still  less. 

Water  absorbs  all  gases,  some  to  a  large  extent, 
others  to  a  very  small  extent.  Hence  the  purest 
distilled  water  will  not  remain  so  but  for  a  very 
short  time.  For  absorption  begins  as  soon  as  the 
stopper  is  removed,  in  fact  has  already  set  in  before, 
unless  the  vessel  had  been  full  up  to  the  stopper. 
As  a  rule  all  absorbed  gases  can  be  expelled  by  pro- 
longed boiling. 


THE    NATURE    OF    WATER.  21 

Chemistry.  The  first  query  will  be :  Is  water  a 
simple,  elementary  body  or  is  it  a  compound? 
Having  observed  that  air  can  be  broken  up  by 
metals  and  by  sulfur  at  a  red  heat,  we  shall  be  con- 
sistent if  we  subject  water  to  the  same  treatment. 
We  start,  therefore,  with  the  assumption  that  water 
is  not  a  simple  body.  The  experiment  will  presum- 
ably proceed  under  proper  conditions  if  a  hard  glass 
tube  T,  Fig.  12,  with  perforated  stoppers  be  placed 
horizontally  with  a  boat  holding  finely  granulated 
zinc  or  iron  filings  in  the  middle  of  the  tube.  A 
glass  syphon  5  reaching  into  the  beaker  is  con- 

FIG.  12. 


nected  by  rubber  1  with  stopper  2  while  a  clamp  3 
permits  a  stop  to  the  flow  of  water  as  well  as  a  regu- 
lation of  the  rate  of  inflow.  A  delivery  tube  5  leads 
just  under  the  surface  of  the  water  in  basin  6  and  a 
test-tube  7  filled  with  water  stands  ready  to  receive 
any  gases  which  might  result  from  the  action. 

Let  the  flame  from  the  burner  B  be  now  put 
under  the  boat  and  water  admitted  drop  by  drop  at 
2  so  that  a  small  pool  forms  behind  the  cork.  As 
the  heat  extends  along  the  glass  tube  the  water  will 


22  CHEMISTRY    SIMPLIFIED. 

begin  to  pass  into  steam  and  the  steam  will  push 
out  the  air.  When  the  latter  is  all  out  the  steam 
will  condense  in  tube  5  and  of  a  sudden  water  will 
rush  from  5  into  T,  will  run  to  the  red  hot  place  at 
the  boat  and  the  T  cracks.  The  apparatus  is  not 
up  to  the  requirements.  Why  should  not  an  iron 
gas  pipe  do  in  place  of  a  glass  tube  ?  Since  we  are 
studying  the  action  of  steam  upon  the  metals  a 
metallic  tube  can  do  no  harm,  and  any  sudden  in- 
rush of  water  cannot  injure  the  tube.  Let  therefore 
a  gas-pipe  of  similar  dimensions  be-  substituted.  A 
further  advantage  of  such  a  tube  will  be  that  a 
higher  degree  of  heat  can  be  applied — say  by  means 
of  a  gas  blow-pipe. 

1.  Action  on  bright  iron  turnings. 

A  gas  is  generated  which  we  collect  in  the  test- 
tube.  It  possesses  an  unpleasant  odor  and  burns 
with  a  faintly  colored  flame.  The  chips  have  lost 
their  brightness,  they  have  become  gray-black,  and 
when  struck  with  the  hammer  a  brittle  scale  comes 
off.  The  scale  is  attracted  by  the  magnet  the  same 
as  the  chips  themselves.  Deduction:  This  scale,  re- 
sembling in  every  respect  ordinary  blacksmith's 
hammer  scale,  which  is  made  by  heating  iron  in 
air,  like  the  other  metal  scales,  leads  us  to  conclude 
that  water  must  contain  oxygen. 

2.  Action  upon  granulated  zinc. 

Gas  of  the  same  character  but  odor  less  pro- 
nounced. The  zinc  is  either  converted  wholly  or 


THE    NATURE    OF    WATER.  23 

partly  into  white  or  grayish-white  powder,  or  into  a 
shining  lustrous  crust,  which  under  the  microscope 
shows  six-sided  prisms  and  pyramids.  Character 
same  as  zinc  oxyd  obtained  in  air. 

3.  Action  upon  copper  turnings. 

Gas  does  not  appear  until  tube  has  become  yellow 
hot,  and  comes  sparingly.  Has  no  pronounced 
odor,  but  burns.  The  copper  has  become  bright 
red  from  the  brittle  copper  oxyd. 

The  three  trials  demonstrate  that  water  is  a  com- 
pound, not  an  element ;  and  further,  that  it  is  an 
oxyd,  in  which  oxygen  is  united  with  the  other 
body,  the  latter  appearing  in  the  free  state  as  a 
light,  odoriferous  gas. 

Reverse  proof  .  Collect  the  gas  in  a  large  bottle  (use 
arrangement  for  collecting  as  in  the  case  of  azote). 
Stand  the  bottle  1  (Fig.  13)  containing  the  gas  up- 
right. Its  stopper  holds  the  long  funnel  tube  #, 
with  rubber  connection  and  clamp  3  and  the  deliv- 
ery tube  4  which  connects  with  the  drying  tube 
the  latter  being  filled  in  the  bulb  with  absorbent 
cotton  and  in  the  cylinder  with  burnt  lime.  Tube 
6  is  drawn  out  into  a  fine  point  (not  too  fine),  and 
the  glass  cylinder,  open  at  both  ends,  is  held  by  a 
clamp  and  stand  as  shown  in  figure.  If  now  water 
be  run  from  the  funnel  into  bottle,  the  water  will 
drive  the  gas  through,  and  if  a  burning  taper 
be  held  to  the  tip  of  6  two  things  can  happen: 
either  a  steady  flame  8  or  an  explosion  which  may 
shatter  the  tubes.  (1  volume  of  the  gas  mixed  with 


24 


CHEMISTRY    SIMPLIFIED. 


2^  volumes  of  air  explodes  violently.)  To  avoid 
explosion,  let  the  gas  go  through  the  tube  for  a 
while — until  the  water  has  risen  in  the  bottle  about 
one  inch — and  then  only  apply  match  or  taper. 
The  flame  is  first  colorless,  but  soon  burns  of  an 
orange-yellow  color.  Why  ?  Because  the  glass,  at 
a  red  heat,  gives  particles  to  the  flame.  Prove  this 

FIG.  13. 


by  placing  a  nozzle  of  silver,  platinum  or  gold  over 
the  tube.  The  flame  will  then  be  invisible  or 
nearly  so,  faintly  purplish. 

But  the  important  part  is  that  immediately  when 
the  flame  appears  the  glass  cylinder  7  becomes 
clouded  and  soon  large  drops  of  liquid  condense 
upon  the  glass  which  will  even  collect  and  run  from 
the  lower  edge  of  the  tube.  We  find  all  the  physi- 


THE    NATURE    OF    WATER.  25 

cal  properties  of  distilled  water  in  this  liquid :  Equal 
weight  per  equal  volume ;  absence  of  taste  and 
smell ;  equal  resistance  to  passage  of  light ;  change 
into  solid  at  0°  C.;  change  into  vapor  at  100°  C.; 
very  high  resistance  to  the  passage  of  the  electric 
current ;  equal  capillarity,  by  which  is  meant  that 
both  liquids  rise  in  a  very  narrow  or  hair  tube 
equally  high  above  the  outer  level.  Therefore,  it 
is  proper  to  apply  the  name  hydrogen  to  this  gas. 
Hydor  =  water,  genomein  =  to  produce: -the  body 
which  produces  water.  It  follows  that  water  must 
be  hydrogen,  oxyd. 

ELECTROLYSIS. 

Next  to  heat  we  find  electricity  as  the  most  in- 
tense force,  or  probably  both  are  only  different 
manifestations  of  the  same  force,  since  heat  can  be 
made  to  generate  electric  current,  and  an  electric 
current  converts  itself  into  heat  under  proper  con- 
ditions. We  will  not  investigate  the  generation  of 
a  current  here  and  simply  assume  it  as  given  ;  you 
will  get  the  explanation  in  physics.  We  simply 
accept  the  fact  that  if  I  fasten  this  wire  to  the  one 
binding  post  on  the  table  and  this  other  wire  to  the 
second  post,  and  if  the  wire  ends  be  brought  in  con- 
tact there  is  now  flowing  a  current  from  one  post  to 
the  other.  If  I  break  the  contact  a  minute  blue 
spark  is  the  visible  proof  that  a  current  was  passing, 
but  does  not  pass  now.  Why?  The  air  space 
between  the  wires  does  not  carry  the  current,  air 
being  a  non-conductor. 


26  CHEMISTRY    SIMPLIFIED. 

In  Fig.  14  a  beaker  glass  is  filled  with  distilled 
water ;  after  bending  the  wires  at  right  angles  I 
sink  the  vertical  portions  into  the  water.  The 
needle  on  this  galvanometer  does  not  move,  hence 
it  follows  that  the  water  between  the  two  wires  is  as 
much  a  non-conductor  as  air ;  of  course  I  speak 
relatively  ;  it  is  a  question  of  tension  or  pressure, 
for  the  current  passes  from  cloud  to  earth  in  a 

FIG.  14. 


thunder-storm,  and  to  say  that  air  and  pure  water 
are  bad  conductors,  will  be  a  better  expression  than 
non-conductors. 

If  we  substitute  this  Houghton-  spring  water  for 
the  distilled  water,  we  see  the  needle  move,  and 
hence  deduce  that  the  earthy  materials  which  are 
dissolved  in  the  water  cause  the  better  conductivity. 
An  addition  of  salt  to  the  water  proves  the  correct- 
ness of  the  deduction.  We  see  not  only  the  diversion 
of  the  needle,  but  we  see  gas  bubbles  rise  from  the 
wires.  The  liquid  conductor  of  the  current  is  called 
electrolyte.  The  wires  dipping  into  the  latter  are 
known  as  electrodes.  The  wire  leading  to  the  posi- 
tive pole  -f  is  the  anode,  the  one  leading  to  the 
negative  pole  --is  the  cathode.  They  are  always 
designated  by  the  -f-  and  —  signs. 


THE    NATURE    OF    WATER. 


27 


If  we  arrange  the  apparatus  as  shown  in  Fig.  15, 
where  2  means  a  test-tube,  filled  with  the  electrolyte, 
and  where  the  electrodes  are  spread,  having  strips 
of  platinum  sheet  soldered  to  themselves,  we  will 
perceive  at  once — the  current  going  through — that 
much  more  gas  arises  from  the  cathode  than  from 
the  anode.  On  applying  a  match  to  the  gas,  after 
the  test-tube  has  been  lifted  out,  there  is  a  strong 

FIG.  15. 


explosive  sound  ;  the  tube  may  be  splintered.  AVe 
call  the  gas  fulminating  (lightning  like).  What  is 
the  nature  of  this  gas?  That  two  different  gases 
are  produced  we  find  indicated  in  the  larger  vol- 
ume of  gas  coming  from  one  of  the  electrodes ;  and 
thus  we  are  led  to  collect  the  two  portions  separately. 
Let  us  take  two  large  test-tubes  B,  B'  (Fig.  16)  and 
blow  into  the  closed  end  two  narrow  tubes  1,  2  be- 
fore the  blow-pipe.  This  requires  some  skill  ac- 
quired by  practice.  To  acquire  such  skill  is  very 
useful  to  any  one  who  wishes  to  become  a  chemist ; 
for  glass-blowers  are  not  always  in  the  neighborhood. 


28 


CHEMISTRY    SIMPLIFIED. 


However,  in  this  case,  we  can  avoid  glass-blowing 
altogether  by  cutting  off  the  closed  end  of  the  tubes 
by  means  of  a  file  and  a  red-hot  glass  or  iron  rod.  In 


FIG.  16. 


B 


B 


Fig.  17  you  see  the  tube  before  and  after  cutting, 
and  only  a  perforated  stopper  is  needed  with  a  nar- 
row glass  tube  tt  to  which  the  short  rubber  tube  with 
spring  or  screw  clamp  and  a  second  bit  of  glass  tube 
are  attached.  Calibrate  now  the  tubes  roughly  into 
cubic  centimeters.  Fill  the  tubes  with  the  elec- 
trolyte, hold  them  by  a  suitable  stand  in  the  basin 
A  (Fig.  16),  and  insert  from  below  the  electrodes 

H .     The  current  being  turned  on  it  soon  becomes 

evident  that  the  gas  volume  in  B'  is  much  larger 
than  in  J5,  that  in  fact  the  two  volumes  are  as  two 


THE    NATURE    OF    WATER. 


29 


to  one.  But  in  E'  we  have  the  negative  pole,  the 
cathode  ;  in  B,  the  positive  pole,  the  anode.  When 
B'  is  filled  with  gas  to  the  electrode  we  stop  the  cur- 
rent ;  draw  out  the  electrode,  shove  a  small  cup 
under  the  tube,  lift  the  latter  and  bring  it  into  a 


B 


B 


wide  cylinder  (a  pail  will  answer,  in  default).  Now 
if  we  press  the  tube  B'  down  into  the  water  until 
there  be  a  difference,  Ht  Fig.  18,  between  the  outer 
and  the  inner  levels,  then  the  gas  will  be  under  a 
pressure  equal  to  the  weight  of  a  column  of  water 
of  the  height  H,  and  if  the  clamp  C  be  cautiously 
opened  the  gas  must  issue  at  P.  We  notice  first  the 
absence  of  any  smell ;  the  absence  of  acidity,  and 
then  apply  a  taper  or  match.  A  flame  appears  at 
the  point.  A  cold  porcelain  dish  held  in  the  flame 
covers  itself  with  moisture.  In  fact  the  gas  acts 
exactly  like  the  Hydrogen  which  we  obtained  pre- 
viously, except  that  it  has  no  odor.  The  former  gas 
must  have  held  some  odoriferous  body  admixed. 
(Supposition  which  must  be  verified  at  a  future 


30 


CHEMISTRY    SIMPLIFIED. 


stage.  As  careful  investigators  we  must  heed  every 
difference  of  action.  In  this  instance  we  shall  find 
that  zinc  and  iron  contain  small  quantities  of  cer- 


tain other  elements,  which  combine  with  hydrogen, 
producing  strongly  smelling  gases.) 

We  proceed  to  operate  now  with  tube  B  (Fig.  16) 
by  transference  to  the  pail  or  large  beaker.  The 
gas  has  neither  odor  nor  taste.  On  bringing  a  match 
over  the  jet  no  flame,  but  the  coal  of  the  match 
burns  with  intense  light.  .  A  piece  of  red-hot  copper 


THE    NATURE    OF    WATER.  31 

or  iron  wire  held  into  the  current,  burns  with  strong 
light  into  a  scale  which  has  all  the  properties  of 
copper  oxyd,  iron  oxyd. 

The  gas  shows  therefore  in  an  intensified  form  the 
behavior  of  air.  It  must  be  oxygen.  That  it  is  only 
oxygen  we  can  prove  by  heating  a  given  volume  of 
iron  or  copper  filings  over  mercury.  On  cooling 
the  mercury  will  fill  the  entire  tube  ;  all  the  gas  has 
been  absorbed. 

Deductions.  1.  Water  is  a  chemical  compound  of 
the  two  simple  bodies,  hydrogen  and  oxygen.  It 
must  be  a  chemical  compound  because  water  is  a  body 
showing  altogether  different  properties  from  those  of 
a  mere  mixture  of  the  gases  as  we  have  it  in  ful- 
minating gas. 

2.  Elements  combine  according  to  simple  ratio  of 
volumes,  as  water  is  composed  by  volume  of  2  hy- 
drogen, 1  oxygen.  If  the  letters  H  and  0  stand  for 
the  two  elements  then  the  symbol 

H20  —  water  =  dihydrogen  monoxyd 

expresses  this  relation. 

Inverse  proof  of  this  proposition. 

Let  E  (Fig.  19)  be  a  graduated  or  calibrated  glass 
tube,  near  the  closed  end  of  which  are  fused  into  the 
glass  2  platinum  wires  (-f-  — ).  Such  a  tube  is  known 
as  eudiometer  =  splendid  or  perfect  measure.  Let  it 
be  furnished  with  a  jacket  J  made  of  a  wide  glass  tube 
(lamp  chimney);  a  cork  C  holds  it  against  the  eudio- 
meter. A  narrow  glass  tube  leads  from  the  boiling 
flask  F  through  the  cork  into  the  jacket ;  th  is  a 


32 


CHEMISTRY    SIMPLIFIED. 


thermometer.  Introduce  about  10  c.c.  of  fulminat- 
ing gas  into  the  eudiometer,  the  mercury  standing 
as  in  the  figure.  If  now  the  water  in  F  be  kept 
hard  boiling  until  the  thermometer  shows  98°  to 
100°  C.,  the  volume  of  the  gas  will  have  increased 
considerably.  Let  us  say  it  reads  11.0  c.c.  Connect 
the  platinum  wires  with  poles  of  an  induction  coil, 
also  known  as  Rhumkorf  coil  from  the  inventors 


FIG.  19. 


name ;  a  spark  will  pass  between  the  platinum  wire 
ends  in  the  eudiometer  with  a  considerable  shock. 
(Hold  the  eudiometer  with  the  hand  to  prevent  its 
being  lifted  clear  of  the  mercury  in  P.)  On  read- 
ing now  the  volume,  we  find  it  shrunk  to  7.3  c.c. 
A  contraction  has  taken  place  of  3.7  c.c.  or  one-third 
of  the  original  volume.  Stop  the  steam,  draw  off 
condensed  water,  and  let  come  to  the  temperature  of 
the  room.  The  mercury  will  rise  steadily  until  it 


THE    NATURE    OF    WATER.  33 

fills  the  entire  tube,  except  a  bubble  of  water  at  the 
very  apex. 

Explanation.  The  high  temperature  of  the  spark 
causes  the  union  of  the  hydrogen  with  the  oxygen, 
and  at  the  temperature  of  100°  C.  water  is  in  the 
form  of  steam.  The  steam  occupies  two-thirds  the 
space  which  was  occupied  by  the  mixture  of  gases. 
The  union  therefore  caused  the  mass  particles  of  the 
gases  to  approach  each  other  at  a  fixed  distance,  so 
that  three  occupy  now  the  space  of  two.  2  vols.  H 
-f-  1  vol.  0  give  2  vols.  steam.  As  the  temperature 
sinks  the  steam  becomes  water  and  thus  the  mer- 
cury can  fill  the  tube  because  the  quantity  of  steam 
expressed  by  7.3  c.c.  corresponds  only  to  a  few  mil- 
ligrams of  water,  for  1  c.c.  of  steam  at  100°  C.  weighs 
0.0005896  gram,  hence  7.3  c.c.  =  0.0043  or  4.3  mil- 
ligrams, which  in  the  form  of  a  drop  of  water  is 
barely  distinguishable  with  the  naked  eye.  The 
11  c.c.  of  gas  must  have  possessed  the  same  weight 
of  4.3  milligrams. 

Law.  Whenever  gaseous  elements  unite  in  the 
ratio  of  2  : 1  a  contraction  of  one-third  ensues. 

Comparing  the  weights  of  the  3  gasiform  ele- 
ments which  we  have  now  discovered  and  studied 
to  some  extent,  we  find  that  hydrogen  :  oxygen  : 
azote  =  1  :  16  : 14.  Oxygen  is  16  times  heavier  in 
equal  volume  than  hydrogen,  and  azote  14  times 
heavier.  Therefore  H20  represents  2  +  16  =  18 
weight  units  and  if  the  smallest  mass  of  each  of  these 
bodies,  still  capable  of  receiving  a  chemical  impetus  and 
acquiring  thereby  an  active  force  or  momentum,  be  de- 
3 


34  CHEMISTRY    SIMPLIFIED. 

signaled  as  atom,  then  the  figures  1,  16,  14  may  be 
designated  atomic  weights,  because  the  ratio  will  be 
the  same  as  long  as  the  volume  is  the  same,  for  the 
largest  as  well  as  the  smallest  units. 

Hydrogen  peroxyd,  H202. 

Under  certain  conditions  H  and  0  can  form  a 
higher  oxyd  or  peroxyd  (per  meaning  beyond).  This 
is  a  body  of  unstable  nature  ;  it  falls  to  pieces  easily 
but  possesses  extraordinary  activity  as  an  oxydizing 
agent.  We  shall  study  the  mode  of  its  preparation 
later  as  well  as  its  application. 


CHAPTER  III. 

GREEN  VITRIOL  OR  COPPERAS. 

UNDER  the  name  copperas,  which  is  the  corrupted 
form  of  the  French  couperose,  and  the  latter  even 
a  corruption  of  the  Latin  cupriaerosa,  which 
means  the  "Rose  of  Cyprus,"  a  substance  of  most 
marked  properties  has  been  known  from  time  im- 
memorial. We  see  it  as  bluish-green  fragments  and 
also  in  the  form  of  large  crystals.  The  symmetry 
of  the  faces  can  be  reduced  to  the  monoclinic  sys- 
tem. Thin  pieces  are  quite  transparent  and  show 
very  little  color ;  because  the  depth  of  color  is  de- 
termined by  the  partial  absorption  of  certain  por- 
tions of  sun  light.  The  thicker  pieces  absorb  more 
light  in  the  transit  of  the  latter  and  therefore  have 
a  deeper  color.  The  substance  is  very  brittle  ;  it  can 
be  crunched  between  the  fingers.  Has  a  strongly  as- 
tringent, bitter-sour  taste,  and  is  quite  soluble  in 
cold  water,  but  very  much  more  soluble  in  boiling 
water.  The  solution  is  not  clear,  but  murky  from 
a  brownish-yellow,  suspended  substance.  By  filter- 
ing through  paper  the  solution  becomes  clear.  If 
such  a  .clear  solution  be  left  standing  exposed  to  the 
air,  one  notices  the  rapid  forming  of  a  yellow  film 
on  the  exposed  surface.  The  film  becomes  thicker 
and  in  time  the  liquid  turns  into  a  yellow  brown, 
(35) 


36  CHEMISTRY    SIMPLIFIED. 

mud-like  fluid.     Query  ?    Has  the  oxygen  of  the  air 
anything  to  do  with  this  change,  or  the  azote  ?    This 
is  easily  settled  by  bringing  some  of  the  fresh,  clear 
solution  into  a  tube  filled  with  azote  and  closing  the 
tube  tight.     No  change  occurs.     Another  portion  in 
a  tube  filled  with  oxygen,  the  film  appears.    Oxygen 
does  the  work.     If  the  solution  of  copperas  comes 
together  with   oak   bark,  the  latter  turns  speedily 
black  (in  reality  deeply  blue-purple).     It  also  turns 
leather  black   because   the  latter  forms   when  raw 
hide  is  allowed  to  soak  in  water  and  ground  oak 
or   hemlock   bark.     We   can   extract   the   leather- 
forming  substance  from  the  bark  by  means  of  water 
and  this  solution  turns  black  with  copperas.     Thus 
came  into  existence  our  black  writing  ink,  already 
known  to  the  ancient  Egyptians.     When  the  extract 
of  bark  is  evaporated  on  a  water-bath,  a  faint  yellow- 
ish  scale,   very   light  and   fluffy,   remains :    tannin 
(from  tan).     Copperas  -f~   water  +  tannin  ==  ink  ; 
mucilage  is  added  to  give  the  ink  a  better  body. 

The  Germans  use  the  word  vitriol  instead  of  cop- 
peras. This  name  was  first  used  by  Pliny  who 
lived  1900  years  ago.  He  describes  the  substance 
as  "  vitriolus  quasi  vitrum"  Vitrum  is  Latin  for 
glass,  the  crystals  resembling  green  glass  were  yet 
easily  soluble  in  water,  while  glass  is  not  soluble. 
Glass  is  fairly  hard,  this  substance  not,  hence  vit 
riolus,  a  kind  of  glass,  like  glass  in  some  ways.  We 
shall  use  the  word  vitriol  as  being  better  expressive 
of  the  substance. 


GREEN    VITRIOL    OR    COPPERAS. 


CHEMICAL   INVESTIGATION  OF  GREEN  VITRIOL. 


37 


Let  a  hard  glass  tube  (J  to  \"  internal  diameter  and 
6  to  8  inches  long)  (Fig.  20)  be  closed  at  one  end  over 
the  gas  blow-pipe.  Hold  the  tube  in  nearly  hori- 
zontal position  or  rather  lower  at  the  open  end,  the 


FIG.  20. 


T  A 

1 

(«=-* 

c 

B 

->                       L_ 

s 

—I 

S' 

—  I 

closed  end  being  charged  with  several  small  pieces 
of  vitriol.  Let  the  tube  be  supported  at  S,  because 
it  has  a  tendency  to  sag  when  the  end  comes  to  a  red 
heat.  It  stands  to  reason  that  the  tube  may  be 
laid  upon  a  couple  of  bricks  for  support.  Let  heat 
be  applied  slowly  with  the  burner  B  to  the  closed 
end,  and  we  will  be  enabled  to  make  the  following 
observations :  1.  A  plentiful  condensation  of  a 
liquid  in  the  cool  part  of  the  tube.  This  liquid 
will  appear  very  mobile,  little  or  no  taste  and  by 
applying  electrolysis  will  give  H  +  0  ;  its  identity 
with  water  is  fixed.  2.  The  vitriol  meanwhile,  is 
partly  melting,  raising  blisters  and  turning  into  a 
white  chalky  mass. 

Deduction  1 :  The  loss  of  water  causes  the  vitriol 
to  become  white  opaque.  We  raise  the  temperature 
to  a  low  redness :  A  strongly  smelling  gas  appears  re- 


38 


CHEMISTRY    SIMPLIFIED. 


calling  the  smell  of  burning  sulfur,  that  is  the  oxyd 
of  sulfur  SnOm.  We  cause  it  to  act  on  indigo  and  lit- 
mus solutions,  the  former  becomes  bleached,  the  lat- 
ter turns  red ;  probability  strong  that  vitriol  contains 
sulfur  oxyd  though  not  certain  yet.  But  remem- 
bering that  copper  oxyd  is  decomposed  by  charcoal 
at  red  heat,  we  may  attempt  the  decomposition  of 
this  suppositious  oxyd  in  the  same  way — and  with- 
out much  of  an  outlay  in  apparatus.  Let  some 


vitriol  be  heated  in  a  porcelain  crucible  until  it 
has  become  white,  that  is,  until  the  greater  part  of 
the  water  has  been  removed,  then  fill  it  into  a  tube 
exactly  the  same  as  before,  that  is,  at  the  closed  end 
a,  Fig.  21.  Let  some  splinters  of  charcoal  be  heated 
in  a  covered  crucible  at  full  red  heat,  and  when  cooled 
down  introduce  them  into  the  tube  at  b ;  stopper  the 
tube  with  cork  and  gas  evolving  tube  t,  the  latter 
leading  into  basin  B  filled  with  water.  The  water 
filled  test-tube  T  is  held  ready  to  be  shoved  over 
the  end  of  t,  when  it  may  be  assumed  that  the  air 
has  been  quite  driven  from  the  apparatus  by  the 


GREEN    VITRIOL    OR    COPPERAS.  39 

evolved  gases.  The  closed  end  a  is  first  brought  to 
redness,  then  the  charcoal  at  b  is  brought  to  dull 
redness,  or  any  other  degree  of  temperature  we  may 
find  advisable.  If  the  gas  be  decomposable  exactly 
as  copper  oxyd  is  decomposed,  we  must  get 

SnOm  +  9  C  =  Sn  +  m  CO  +  (9  —  m)  C., 

but  since  sulfur  is  a  non-metal,  it  is  quite  probable 
that  compounds  of  S  and  C  are  generated,  for 
which  we  must  look  out.  The  glass  tube  is  best 
supported  by  two  bricks,  -P,  P',  stood  up  on  edge. 
In  order  to  facilitate  the  deposition  of  sulfur  we 
protect  the  part  of  the  tube  beyond  the  charcoal 
with  a  diaphragm  or  screen  d.  The  latter  can  be  a 
slotted  piece  of  sheet-iron  or  a  piece  of  asbestus 
board.  As  soon  as  the  charcoal  becomes  red  at  one 
spot,  we  notice  a  film  forming  before  the  diaphragm, 
which  increases  in  bulk,  forming  yellow  and  yellow- 
brown  drops.  The  water  in  the  basin  becomes  tur- 
bid, milky,  and  a  gas  of  peculiar  smell  collects  in 
the  test-tube.  What  causes  the  milkiness  ?  What  is 
the  peculiar  smell  due  to  ? .  These  questions  we  shall 
not  attempt  to  answer  at  this  juncture,  but  place 
them  on  the  calendar  for  future  study  and  explana- 
tion. We  let  the  tube  cool  down,  cut  it  with  file  and 
hot  glass  rod  at  the  diaphragm,  and  subject  the  yellow 
film  to  two  tests,  (a)  We  scratch  out  a  portion  of  the 
unknown  yellow  substance,  place  it  upon  a  piece  of 
bright  silver  foil,  and  heat  it  over  a  flame,  until  the 
foil  is  barely  red  hot.  When  cold  a  black  spot  or 
possibly  a  hole  will  appear,  where  the  unknown 


40  CHEMISTRY    SIMPLIFIED. 

substance  was  placed,  the  silver  has  formed  a  black 
compound  and  this  is  characteristic  for  sulfur,  (b) 
We  hold  the  tube  inclined  to  get  draught  and  heat 
the  film  in  the  flame ;  we  get  the  pungent  odor  of 
burning  sulfur.  No  doubt  can  remain,  vitriol  con- 
tains sulphur  oxyd,  or  at  any  rate  we  can  say  that 
this  gas  is  one  of  the  products  when  vitriol  is 
broken  up  by  heat. 

Now  let  us  return  to  the  original  experiment 
which  we  left  in  order  to  prove  the  sulfur  oxyd. 
We  apply  now  a  very  hot  flame  (best  from  a  Bunsen 
gas  blow-pipe)  to  the  vitriol.  White  clouds  appear 
in  the  tube  and  roll  out  of  the  latter ;  the  substance  of 
this  fume  is  evidently  heavier  than  air.  The  action 
of  it  upon  the  mucous  membrane  is  energetic,  for  a 
suffocating  sensation1  is  caused  by  inhaling  it.  It 
causes  the  muscles  of  the  larynx  to  contract  vehe- 
mently. At  the  same  time,  with  the  appearance  of 
the  fumes,  we  notice  a  thick  liquid  condensing  at  a 
little  distance  from  the  heated  end  of  the  tube.  We 
let  the  latter  cool  down  and  cut  it  off  just  at  the 
liquid  ring ;  as  the  two  pieces  come  apart  another 
installment  of  white  fume  appears.  Why?  We 
apply  litmus-paper  to  the  liquid  ;  it  turns  intensely 
red,  but  soon  after  turns  brown,  and  finally  the 
rim  gets  black ;  the  paper  has  been  charred.  De- 
duction :  The  liquid  possesses  qualities  of  an  ex- 
traordinary nature.  The  great  experimenter  who 
discovered  it  in  the  10th  century,  the  Moor  Geber 
in  Spain,  gave  it  an  Arabic  name  which  was  trans- 
lated into  Latin :  oleum  vitrioli — the  oil  of  vitriol, 


GREEN    VITRIOL    OR    COPPERAS. 


41 


owing  to  its  sluggishness  in  flowing  like  a  thick  olive 
oil,  and  because  it  produced  a  lubricating  of  the 
skin  when  rubbed  between  the  fingers.  In  order  to 
study  the  substance,  we  must  design  an  apparatus 
which  will  allow  the  treatment  of  a  considerable 
quantity  of  the  vitriol,  say  one  pound.  Since  we 
noticed  that  the  glass  became  quite  soft  and  even 
collapsed  when  exposed  to  the  high  temperature  of 
the  blow-pipe,  we  must  look  out  for  a  material 
which  will  remain  solid  as  well  as  rigid  at  such  a 
temperature.  Fire-clay  is  such  a  material.  Its 

FIG.  22. 


plasticity  when  mixed  with  water  makes  it  capable 
of  being  moulded  into  any  desired  form.  When 
carefully  dried  and  then  equally  carefully  baked, 
it  becomes  hard,  fire-resisting,  and  fairly  gas-tight. 

In  Fig.  22  we  see  the  section  of  a  fire  clay  retort 
inside  of  a  fire-brick  lined  furnace,  which  is  heated 
by  a  gasoline  flame  F.  Before  filling  the  vitriol 
into  the  retort,  we  heat  it  in  an  open  dish  or  large 
crucible  until  all  the  water  is  driven  out,  and  until 
it  has  turned  a  light  brick  red,  that  is,  at  a  low  red 
heat,  since  we  only  care  for  the  white,  cloudy  fumes 


42  CHEMISTRY    SIMPLIFIED. 

and  not  for  the  sulfur  oxyd.  Then  we  fill  the  ma- 
terial V  through  the  tubulature  at  S  and  fasten  the 
stopper  or  plug  by  means  of  pasty  fire-clay.  Over 
the  neck  of  the  retort  N,  we  pass  the  neck  of  the 
large  glass  flask  R  loosely,  to  furnish  exit  for  the 
gases.  The  flask  we  bed  into  a  mixture  of  salt  and 
broken  ice  (freezing  mixture)  contained  in  a  basin  1 
and  over  the  upper  side  of  the  flask  we  spread  a 
muslin  bag  I'  filled  with  the  same  mixture.  Why  ? 
In  order  to  expose  a  maximum  of  cold  surface  to  the 
fumes,  having  seen  in  the  preliminary  experiment 
that  the  fumes  do  not  condense  at  the  ordinary  tem- 
perature. The  lid  of  the  furnace  having  been  put 
in  place,  we  light  the  flame  under  strong  air  pressure 
and  soon  the  retort  will  show  cherry  redness  on  the 
outside.  But  since  the  fire-clay  wall  of  the  retort  is 
but  a  poor  transmitter  of  heat,  some  further  time 
must  elapse  until  the  material  Fgets  to  that  temper- 
ature. Then  we  see  the  white  fumes  pouring  into  the 
flask,  falling  like  a  foaming  cataract  to  the  bottom 
and  also  issuing  at  the  neck  of  the  flask.  Hence  the 
apparatus  should  stand  under  a  good  up  draft  or 
alongside  a  good  down  draft.  The  heat  will  be  mod- 
erated or  increased  according  to  the  volume  of  white 
vapor  issuing  from  the  neck  N.  If  no  more  fume 
comes — say  after  two  hours — even  at  a  yellow  heat 
of  the  retort,  we  stop  the  operation.  We  remove  the 
basin  I  and  the  bag  I'  and  wipe  the  outside  of  the 
flask  dry.  Three  facts  are  observable  :  A  brownish 
thick  liquid  about  50  c.c. ;  snow-like  crystals  of  needle 
shape  all  over  the  flask  ;  and  a  dense  fume  still  filling 


GREEN    VITRIOL    OR    COPPERAS.  43 

the  flask.  We  pour  the  liquid  into  a  large  test-tube, 
or  into  a  smaller  flask.  During  this  operation  quan- 
tities of  the  white  fumes  arise  suffocatingly  from  the 
liquid,  wherever  the  air  touches  it.  Query  ?  Which 
constituent  of  the  air  causes  this  action?  Azote, 
oxygen  or  the  water  vapor  ?  By  experimental  elim- 
ination we  fix  the  action  upon  the  water  vapor  = 
moisture,  of  the  air.  Withaut  moisture  no  fumes. 
Hence  it  follows  that  the  roasted  vitriol  must  still 
contain  some  water,  or  else  we  could  not  see  the 
fumes  inside  the  glass  tube  in  our  first  experiment. 

Two  immediate  investigations  must  now  be  un- 
dertaken ;  we  must  first  try  to  get  at  the  inwardness 
of  the  crystallized  substance,  and  secondly,  of  the 
liquid  substance. 

a.  Investigation  of  the  oil  of  vitriol,  the  liquid 
substance.  If  put  upon  the  skin,  a  drop  will  raise  a 
blister  and  actually  burn  a  hole  into  the  flesh,  de- 
stroying the  tissue  thoroughly. 

Brought  together  with  a  drop  of  water  a  hissing 
sound  is  caused.  If  water  be  splashed  or  poured 
into  a  larger  quantity  of  the  oil,  so  much  steam  is 
generated  by  the  evolution  of  heat,  that  the  liquid 
is  thrown  violently  from  the  vessel  and  has  often 
injured  the  careless  operator.  Paper  is  charred 
into  a  slimy,  black  substance  by  the  oil.  White 
sugar  arid  starch  are  changed  into  the  same  black 
substance. 

The  oil  smells  strongly  of  the  sulfur  oxyd  gas, 
and  when  heated  emits  white  fumes,  until  at  the 
end  a  liquid  results,  nearly  colorless,  which  does 


44 


CHEMISTRY    SIMPLIFIED. 


not  fume  at  the  air,  and  does  not  smell  of  sulfur 
oxyd.  This  colorless  liquid  boils  at  326°  C.  (a  very 
high  temperature),  giving  likewise  dense  white 
fumes  to  the  air,  when  boiling,  which  condense  into 
a  colorless  heavy  liquid,  thus  differing  from  the  white 
fumes  of  the  oil,  which  condense  into  a  snowy  solid. 
With  an  arrangement  as  in  Fig.  23,  we  can  prove 

FIG.  23. 


these  points.  In  the  small  retort  on  the  left  of  the 
figure  we  place  some  10  c.c.  of  the  oil  of  vitriol, 
using  a  long-stemmed  funnel,  so  that  the  neck  shall 
not  be  moistened  with  the  liquid. 

At  3  we  have  a  thermometer  not  reaching  into 
the  liquid  ;  fasten  it  into  the  tubulature  with  asbestus 
thread.  The  retort  is  held  by  a  clamp  from  stand 
4.  At  5  we  have  a  U-tube  connected  by  a  narrow 
tube  with  the  neck  of  the  retort  through  a  cork.  The 
U-tube  is  also  fitted  with  perforated  stoppers  and 
stands  between  broken  ice — or  snow — in  the  beaker 
glass  6.  Any  liquid,  condensing  in  the  retort's  neck, 


GREEN    VITRIOL    OR    COPPERAS. 


45 


will  flow  back.  Heating  with  burner  8  using  a  very 
small  flame,  we  soon  get  the  smell  of  sulfur  oxyd  alone 
at  7,  and  later  on  associated  with  white  fumes.  At 
the  same  time  the  walls  of  the  U-tube  become  frosted 
over  with  white,  needle-shaped  crystals.  When  the 
temperature  has  risen  to  300°  C.,  we  stop  heating  and 
remove  the  U-tube  ;  noticing  the  fumes  arising  from 
the  cold  substance  in  the  tube,  as  soon  as  moist  air 
comes  in  contact  with  it.  Now  let  us  change  the* 
position  of  the  retort  by  turning  the  swivel  of  the 

FIG.  24. 


clamp  holder.  The  neck  points  downward,  Fig.  24, 
and  reaches  into  a  dry  test-tube.  Raise  the  heat 
so  that  the  liquid  gets  into  boiling  commotion. 
Streaks  and  streamers  of  thick  liquid  will  run  down 
the  neck  and  collect  in  the  test-tube  8.  Hence  it 
follows  that  by  heat  we  can  split  the  oil  of  vitriol 
into  three  parts :  a  gas  (sulfur-oxyd);  a  solid  (?);  a 
liquid  residue  (?).  The  question-marks  stand  for : 
must  be  found  out. 

The  liquid  residue.     Let  it  be  acted  upon  by  the 
metals.    Bring  about  2  c.c.  of  the  liquid  in  a  test-tube 


46  CHEMISTRY    SIMPLIFIED. 

together  with  a  piece  of  copper  foil.  No  action  is 
noticeable  until  we  heat,  when  effervescence  ensues. 
(Effervescence  means  frothing  due  to  rapid  produc- 
tion of  gas  bubbles  in  a  liquid.)  The  smell  charac- 
terizes the  escaping  gas  as  sulfur  oxyd.  Further  we 
notice  the  forming  of  a  grayish,  granular  substance, 
and  the  copper  foil  has  disappeared  ;  it  has  become 
changed  or  converted  into  the  white  granular  sub- 
stance. These  interesting  facts  lead  us  to  a  suppo- 
sition or  hypothesis  that  our  liquid  must  contain  an 
oxyd  of  sulfur  containing  more  oxygen  than  the  gasi- 
form oxyd.  If  the  latter  be  symbolized  as  SnOm, 
then  the  hypothetical  oxyd  would  be  SnOm+p  in 
which  symbol  p  denotes  the  mass  units  of  oxygen 
which  were  given  over  to  the  copper  enabling  the 
latter  to  go  into  solution,  through  the  abstrac- 
tion of  this  oxygen  from  the  higher  oxyd  to  form 
the  lower  sulfur  oxyd  with  its  characteristic  smell. 
But  in  order  to  verify  the  supposition  we  must  ex- 
amine the  white  granular  product  of  the  action.  We 
pour  off  the  liquid,  add  water  to  the  granular  resi- 
due, and  see  it  go  rapidly  into  solution  with  a  pale- 
blue  color.  The  solution  we  evaporate  on  a  water- 
bath.  At  a  certain  point  of  the  evaporation  a  solid 
begins  to  form.  We  allow  the  liquid  to  cool  and  a 
larger  crop  of  blue  crystals  will  form.  The  crystals 
are  translucent,  show  an  oblique  symmetry,  in  fact 
resemble  the  crystals  of  our  original  vitriol.  Hence 
the  deduction  will  be  rational  that  the  crystals  are 
copper  vitriol.  (A  crystal  placed  upon  a  knife  blade 
with  a  drop  of  water  produces  a  bright  copper  spot 


OF    THE 

UNIVERSITY 

OF 

COPPERAS.  47 


upon  the  blade.)  We  dry  the  crystals  between  filter 
paper  and  bring  some  into  a  closed  tube.  On  heating, 
as  in  the  original  experiment,  we  observe  water  first, 
and  the  vitriol  turns  white.  At  higher  heat,  full 
redness,  we  note  some  sulfur  oxyd  gas,  and  at  still 
higher  heat,  when  the  glass  begins  to  melt,  a  ring 
of  oily  liquid  (oil  of  vitriol).  On  cooling  the  vitriol 
has  become  jet  black,  and  the  black  body,  under  the 
circumstances  is  evidently  copper  oxyd.  The  chain 
of  evidence  is  complete.  This  copper  oxyd  must 
have  been  contained  in  the  copper  vitriol.  And  hav- 
ing put  metallic  copper  into  the  liquid,  the  copper 
oxyd  can  only  have  formed  by  taking  oxygen  from 
a  higher  oxyd  present.  The  latter  is  an  oxyd  of 
sulfur,  because  sulfur  oxyd  forms  during  the  opera- 
tion. We  symbolize  the  operation  or  action  thus  : 

pCu  +  2pSnOm+P  =  pCuO.SnOm+P  +  pSnOm. 

A  vitriol  thus  defines  itself  as  the  combination  of 
a  metallic  oxyd  with  sulfur  peroxyd,  the  syllable  per 
meaning  more.  Both  vitriols  contain  water,  but 
that  does  not  mean  that  all  vitriols  must  contain 
water. 

ACTION  OF  THE  LIQUID  RESIDUE  UPON  LEAD  AND 
SILVER. 

If  we  bring  a  piece  of  lead  foil  or  very  thin  'sheet 
lead  into  a  test-tube  with  the  liquid  residue,  there  is 
no  action  at  the  ordinary  temperature.  On  heating 
we  notice  a  whitish  film  on  the  metal  which  again 
disappears.  But  on  further  heating  there  is  at  once 


48  CHEMISTRY    SIMPLIFIED. 

an  impetuous  action,  with  formation  of  sulfur  oxyd 
gas  and  a  very  fine  granular  white  substance.  Like- 
wise a  yellow  streak  appears  in  the  upper  part  of 
the  tube.  Lead  vitriol  is  white  and  remains  white 
when  we  add  water,  and  furthermore  does  not  dis- 
solve even  in  a  very  large  amount  of  water.  We 
collect  the  white  substance  on  a  filter,  wash  it  thor- 
oughly and  let  it  become  dry  in  the  air.  In  the 
closed  tube,  when  heated  to  redness  it  gives  no  water, 
but  over  the  gas  blow-pipe  it  decomposes  leaving 
yellow  lead  oxyd,  the  latter  entering  into  combina- 
tion with  the  glass  at  this  high  heat,  forming  a 
yellow  transparent  compound. 

The  yellow  streak  on  the  upper  tube  we  can 
readily  prove  to  be  sulfur.  We  crack  off  the  tube 
near  the  streak,  wash  thoroughly  with  water,  dry 
and  then  heat  over  a  flame.  The  yellow  streak  will 
melt  and  then  burn  with  a  blue  flame,  giving  the 
smell  of  sulfur  oxyd.  This  fact,  teaches  us  that, 
while  under  ordinary  conditions  a  metal  takes  from 
sulfur  peroxyd  only  enough  oxygen  to  convert  the 
peroxyd  into  the  oxyd,  under  extraordinary  condi- 
tions of  stimulated  chemical  activity,  the  oxygen 
may  be  taken  away  altogether  from  the  peroxyd, 
leaving  sulfur  in  the  free  state. 

We  bring  a  piece  of  silver  foil  into  the  liquid 
residue  and  heat,  when  action  sets  in,  the  foil  dis- 
appearing, without  being  changed  into  a  solid  res- 
idue ;  in  other  words,  the  silver  vitriol  is  soluble 
in  the  liquid.  If  water  be  added  to  the  cooled 
liquid,  cautiously,  a  white  crystalline  powder  will 


GREEN    VITRIOL    OR    COPPERAS.  49 

soon  fall  out,  but  will  again  dissolve  when  much 
water  is  added,  that  is,  the  silver  vitriol  is  soluble 
in  water  and  soluble  in  the  concentrated  liquid 
residue,  but  not  soluble  in  the  moderately  dilute 
liquid  residue.  Of  the  solution  of  the  silver  vitriol 
we  will  soon  be  able  to  make  some  important  use. 
Gold  is  not  attacked  by  the  liquid  residue,  and  hence 
a  very  important  deduction  follows  that  if  gold  and 
silver  are  united  in  the  form  of  an  alloy,  they  may 
be  separated  by  means  of  this  liquid  residue,  and  are 
thus  separated  in  the  Mint  and  the  Metal  Refineries. 

INVESTIGATION  OF  THE   SOLIDIFIED  OR  CRYSTALLIZED 
WHITE    FUMES. 

We  take  now  the  U-tube  which  contains  the  snowy 
deposit.  We  notice  the  inner  surface  of  the  corks 
strongly  blackened  (same  action  as  shown  by  the  oil 
as  well  as  the  fumes,  even  at  ordinary  temperature). 
On  pulling  the  cork  white  fumes  develop  (again  like 
the  oil).  We  let  a  drop  of  water  run  down  the  side 
of  the  glass.  A  hissing  noise  is  produced,  and  a  drop 
of  heavy,  oily  liquid,  runs  to  the  bend  of  the  U.  By 
adding  drop  after  drop  of  water,  we  convert  all  the 
solid,  snowy  substance  into  the  brownish-colored 
liquid,  which  latter,  by  this  time,  has  become  burn- 
ing hot.  We  act  with  this  liquid  upon  the  metals 
as  we  did  with  the  Liquid  Residue.  The  action  is 
exactly  the  same  in  both  cases,  forming  vitriol  and 
sulfur  oxyd.  Hence  it  follows  that  the  solid  product 
from  the  distillation  of  the  oil  of  vitriol,  or  in  other 
words,  the  white  fume  must  be  sulfur  peroxyd.  But 
4 


50  CHEMISTRY    SIMPLIFIED. 

then  it  follows  inversely  that  if  the  sulfur  peroxyd 
be  converted  by  water  into  a  liquid,  whose  action  is 
the  same  as  the  Liquid  Residue,  then  the  latter 
must  be  sulfur  peroxyd  plus  water.  Stated  sym- 
bolically this  means — 

White  fume  =  SnOm+p  =  Sulfur  peroxyd. 

Liquid  Eesidue  ==  SnOm+P.  H20  =  Sulfur  per- 
oxy-hydroxyd. 

Sulfur  oxyd  =  SnOm. 

Oil  of  Vitriol  =  SnOm  +  P. H20  +  SnOm+P  +  SnOm. 

And  since  sulfur  oxyd  and  sulfur  peroxyd  are 
expelled  from  the  oil  by  heat,  we  express  the  pre- 
vious condition  by  saying :  Sulfur  oxyd  and  sulfur 
peroxyd  are  dissolved  in  the  sulfur  peroxy-hydroxyd, 
and  thus  form  the  oil  of  vitriol.  The  latter  is  a 
stable  compound  of  the  two  oxyds,  which  cannot  be 
broken  up  by  boiling ;  it  distills  over  at  326°  C. 
without  decomposition.  Instead  of  saying  sulfur 
peroxy-hydroxyd  we  will  say  in  future  sulfuric  acid, 
because  the  substance  has  eminently  the  characters 
of  an  acid  body ;  but  the  other  name  expresses 
better  its  make-up. 

DIRECT    PROOF    OF    THE    PRESENCE    OF  WATER  IN  THE 
SULFURIC  ACID. 

By  holding  before  us  the  actions  of  this  sub- 
stance upon  the  metals  which  we  have  observed  we 
can  deduce,  among  others,  the  following  reasoning  : 
(a)  If  lead  is  converted  by  the  acid  into  a  vitriol, 
i.  e.,  a  combination  of  lead  oxyd  with  sulfur  per- 
oxyd plus  sulfur  oxyd  we  must  get  lead  vitriol  also. 


GREEN    VITRIOL    OR    COPPERAS.  51 

by  bringing  together  lead  oxyd  plus  sulfuric  acid 
without  the  forming  of  sulfur  oxyd.  (b)  Lead  vit- 
riol does  not  take  up  water,  (c)  Therefore  if  we 
mixed  thoroughly  an  excess  of  yellow  lead  oxyd 
with  a  certain  quantity  of  sulfuric  acid,  then  the 
water  must  be  liberated  if  any  be  contained  in  the 
acid. 

In  order  to  reduce  the  argument  to  trial,  we  shall 
mix  5  c.c.  of  concentrated  sulfuric  acid  with  50 
grams  of  yellow  lead  oxyd  in  a  small  wedge-wood 
mortar  until  the  paste  is  almost  powder.  We  fill 
this  into  a  test-tube.  Place  the  latter  in  a  horizon- 
tal position  as  shown  in  Fig.  25,  where  1  is  the  tube 

FIG.  25. 
I  H 

MA     T4.  w        V         J 


holding  the  mixture  3/  with  a  delivery  tube  passing 
through  the  jacket  J  fed  with  cold  hydrant  water  H, 
which  runs  through  the  discharge  tube  D  into  the 
sink.  Almost  at  once,  after  applying  a  flame  gently 
back  and  forth  under  Jf,  a  condensation  of  mobile 
liquid,  water  in  fact,  takes  place  at  Wt  much  steam 
passes  into  the  tube,  is  condensed  by  the  cold  jacket 
and  collects  in  test-tube  R.  The  first  distillate  is 


52  CHEMISTRY    SIMPLIFIED. 

nearly,  not  altogether,  pure  water.  It  will  show 
acid  reaction  to  litmus  ;  but  if  one  cubic  centimeter 
be  drawn  out  and  weighed,  the  weight  will  be  so 
nearly  one  gram,  that  for  our  purposes  we  may  ac- 
cept it  as  one  gram  and  thus  experimentally  show 
the  sameness  with  water.  We  have  proved  that 
sulfuric  acid  is 


or  in  other  words  that  it  is  a  vitriol  in  which  hy- 
drogen oxyd  takes  the  place  of  other  metallic  oxyds. 
SO2.  We  have  arrived  at  a  stage  of  development 
when  we  will  be  able  to  reason  out  the  ratio  in 
which  sulfur  and  oxygen  are  united  in  the  gasiform 
sulfur  oxyd.  Let  us  make  a  bent  (knee-shaped)  tube 
K,  Fig.  26.  Fill  it  with  mercury  and  hold  it  with  a 


proper  clamp  and  stand  in  the  mercury  trough  P. 
By  heating  a  certain  peroxyd  (known  as  potassium 
chlorate)  in  a  test-tube  we  can  easily  make  pure 
oxygen  gas  and  cause  it  to  rise  in  the  knee-tube 
until  the  mercury  shall  drop  to  an  arbitrary  mark 
M.  We  will  then  shove  a  piece  of  sulfur  under  the 
opening  and  let  it  rise  to  the  surface.  A  piece  of 
soft  copper  wire  rolled  into  a  spiral  at  one  end  will 


GREEN    VITRIOL    OR    COPPERAS.  53 

enable  us  to  push  the  sulfur  to  the  end  of  the  tube 
at  5.  A  strip  of  gummed  paper  can  now  be  used  to 
mark  the  new  mercury  level.  If  a  flame  be  now 
brought  under  5,  by  slow  degrees  to  avoid  crack- 
ing the  glass,  then  5  be  strongly  heated  to  the 
point  of  ignition  of  sulfur,  we  will  suddenly  see 
the  mercury  get  into  strong  up-and-down  motion. 
This  means  that  union  between  sulfur  and  oxygen 
has  taken  place.  Heating  is  stopped  when  the  mer- 
cury has  become  quiet.  When  the  apparatus  has 
returned  to  the  temperature  of  the  room,  we  find 
that  the  mercury  has  risen  to  the  mark.  Hence  it 
is  evident  that  oxygen  changes  into  sulfur  oxyd 
without  change  of  volume.  Or  we  can  say  one  vol- 
ume of  SnOm  contains  one  volume  of  O.  But  how 
much  sulfur  has  entered  into  the  volume?  Evi- 
dently we  find  this  by  subtracting  the  weight  of  one 
volume  of  oxygen  from  the  weight  of  one  volume  of 
SnOm.  Let  the  latter  be  W  and  the  former  W, 
then 

W  .  _  W  ==  S'  (weight  of  sulfur  in  the  gas). 
Now  we  need  only  to  know  how  much  one  vol- 
ume of  sulfur  weighs  to  solve  our  problem.     These 
values  have  been  determined  and  reduced  to  air  as 
unity ;  they  are 

1  vol.  SnOm  ==  2.210  :  hence  W— W=  (2.21  — 1.105) 
1vol.  0  -1.105:  =1.105 

1  vol.    S      =2.200:  =  S' 

:  so  S'  =  J  S 

:  because    -l— -  — 


54  CHEMISTRY    SIMPLIFIED. 

hence  follows  SO2  as  expressing  the  volume  ratio 
between  the  two  bodies. 

Thus  we  see  that  1J  volumes  of  the  free  gases 
when  combined  only  occupy  one  volume — con- 
densation of  one-third.  The  same  was  true  of 
hydrogen  and  oxygen  when  they  combined  to  water. 

If  the  true  numerical  symbol  for  sulfur  oxyd  be 
SO2,  which  we  necessarily  pronounce  sulfur  dioxyd, 
what  is  the  symbol  of  the  sulfur  peroxyd?  The 
answer  is  SO3.  You  will  prove  this  yourselves  at  a 
later  stage  of  this  course,  and  just  simply  accept  the 
fact.  The  vitriols  are  therefore  : 

H2O.S03  =Hydroxyd  vitriol  =  Sulfuric  acid. 

CuO.SO3  =  Copper  oxyd  vitriol  =  Copper  vitriol. 

PbO.SO3  =Lead  oxyd  vitriol  =  Lead  vitriol. 

ZnO.SO3  =  Zinc  oxyd  vitriol  =  Zinc  vitriol. 

FeO.S03=Iron  oxyd  vitriol  =  Iron  vitriol  = 
copperas. 

Ag2  0. SO  8  =  Silver  oxyd  vitriol  =  Silver  vitriol. 

The  writing  of  silver  oxyd  Ag20  is  based  upon 
experiments  and  reasonings  which  we  cannot  now 
go  into,  but  which  will  appear  shortly. 

The  dilution  of  sulfuric  acid.  If  we  make  that 
experiment  in  which  we  proved  the  presence  of 
water  in  the  liquid  residue  or  the  concentrated  sul- 
furic acid,  with  great  care,  weighing  the  acid  taken 
and  weighing  the  water  which  results,  we  obtain  in 
a  given  experiment,  when  we  took  20.54  grams  of 
the  acid,  3.77  grams  of  water;  hence  the  concen- 
trated acid  contains  in  20.54  grams:  SO3  equal 
16.77;  H20  =  3.77.  We  also  know  that  S  =  20, 


GREEN    VITRIOL    OR    COPPERAS.  55 

that  is,  the  sulfur  as  gas  weighs  for  equal  volumes 
twice  the  oxygen,  S  =  32,  therefore 
1    sulfur  =  32  X  1  =  32.     Also  2H  =    2x1=    2 
3  oxygen  =  16  X  3  =  48.     1  oxygen  =  16  X  1  =  16 

Sum     80  Sum     18 

The  numbers  80  and  18  stand  for  the  mass  units  of 
SO3  and  IPO,  or  as  other  chemists  say,  they  repre- 
sent their  molecular  weights.    The  experiment  gave  us 
SO3  =16.77:  80  =  0/2096:  1 
H  0=  3.77:  IS  =  0.2094  '-  1 

By  dividing  into  these  numbers  the  molecular 
weights,  we  change  the  weight  numbers  into  molec- 
ular quantities.  We  get  equal  quotients  and  have 
thus  established  that  the  symbol  H2O.S03  is  the 
true  quantitative  expression  for  that  concentrated 
acid,  which  distills  without  breaking  up. 

We  take  this  concentrated  acid  and  add  water, 
mixing  the  two ;  the  mixture  becomes  hot.  We 
conclude  of  necessity  that  a  chemical  union  has 
been  effected.  Let  the  addition  of  water  be  rational 
instead  of  arbitrary.  Let  the  quantity  of  concen- 
trated acid  taken  be  100  grams,  which  contain  :  SO3 
=  81.6  ;  IPO  =  18.4.  By  adding  with  a  graduated 
tube  or  cylinder  18.4  c.c.,  we  will  have  added  just 
one  other  mass-unit  of  water ;  the  resultant  liquid 
will  be 

H2O.S03.H20  =  ml/uric  acid  monohydrate, 
containing  in  100  parts  :  SO3  =  68.9  ;  IPO  =  31.1. 
After  this  liquid  has  resumed  the  normal  tempera- 


56  CHEMISTRY    SIMPLIFIED. 

ture  of  the  room,  we  take  of  it  again  100  grams,  add 
to  this  18.4  grams  of  water,  and  mixing,  find  again 
a  rise  of  temperature,  but  much  less  than  before. 
Unquestionably  another  chemical  union  of  lesser 
strength  of  hold,  the 

H2O.S03.2H20  =  sulfuric  acid  dihydrate, 
containing  in  100  parts  :  SO3  =  58.2  ;  H20  =  41.8. 
Repeating  the  operation  a  third  time  a  very  slight 
rise  in  temperature  follows.     Hence  we  conclude 
that  the 

H2O.S03.3H20  ==  sulfuric  acid  trihydrate, 
containing  in  100  parts  :  SO3  =49.2  ;  IPO  =50.8 
is  the  last  hydrate.     Beyond  this  figure  water  is  not 
held  in  chemical,  only  in  mechanical,  union,  which 
we  can  very  properly  express  by  the  symbol 
H2O.S03.3H20  +  aq., 

in  which  aq.  stands  for  Latin  aqua  ==  water  ;  this 
is  dilute  acid. 

ACTION    OF    HYDRATES    OF   SULFURIC    ACID  UPON    THE 
METALS. 

The  mono-  and  di-hydrate  act  in  a  boiling  solution 
the  same  as  the  acid  upon  lead  and  copper,  that  is, 
SO2  is  disengaged  and  the  vitriols  form.  The  trihy- 
drate does  not  act  upon  lead  or  copper.  .  But  if  we 
bring  this  trihydrate  upon  zinc  or  iron  a  violent  evo- 
lution of  gas  results.  The  gas,  however,  is  not  SO2. 
It  has  a  peculiar  odor,  more  marked  with  the  iron 
than  with  the  zinc.  But  the  gas  is  inflammable, 
and  if  the  flame  is  inside  a  cold  test-tube,  water 


GREEN    VITRIOL    OR    COPPERAS.  57 

condenses  fast.  The  gas  is,  therefore,  mostly  hydro- 
gen ;  the  odor  coming  from  other  bodies  contained 
in  the  iron  and  zinc,  so-called  impurities.  The  pro- 
cess may  be  represented  by  symbols,  thus 

H2O.S03.3H20  +  aq.  +  Zn  ==  ZnO.SO3  +  3H20 

-h  aq.  +  H2, 

for  if  the  liquid  be  evaporated  after  the  action,  zinc 
vitriol  crystallizes.  In  other  words,  we  may  de- 
scribe the  process  thus :  Zinc  oxyd  has  a  stronger 
tendency  to  form  vitriol  than  hydrogen  oxyd.  The 
zinc  therefore  takes  the  oxygen  away  from  the  latter 
and  thus  liberates  hydrogen.  We  may  extend  this 
idea  to  the  former  reaction,  where  SO2  is  evolved, 
thus 

Zn  +  H2O.S03  ==  ZnO.SC8  +  H2. 
H2  +  HaO.S08  ==  SO2  +  2H2O. 

The  power  inherent  in  "  nascent "  hydrogen  is  such 
that  it  will  decompose  SO3  into  SO2  -j-  IPO,  but 
this  power  does  not  exist  in  the  dilute  solution.  The 
result  is  just  the  same  as  if  we  say  the  metal,  zinc 
for  instance,  takes  the  oxygen  from  SO3. 

Acting  upon  iron  chips  with  dilute  sulfuric  acid, 
we  get  finally  a  muddy,  dark -colored  solution  and 
the  hydrogen  gas  is  strongly  tainted  with  other  gas 
of  a  fetid,  unpleasant  odor.  When  the  liquid 
stands,  it  gradually  becomes  clear  with  a  bluish- 
green  color,  a  black  sediment  having  fallen  to  the 
bottom.  We  remove  this  by  filtration  and  find  that 
the  dried,  black  substance  can  be  burnt  like  coal ;  it 
is  a  peculiar  kind  of  coal  called  graphite,  and  the 


58  CHEMISTRY    SIMPLIFIED. 

fetid  gas  is  a  combination  of  the  coal  with  hydrogen 
(CnHm).  Zinc  likewise  leaves  a  residue,  but  this 
does  not  burn.  We  shall  see  at  a  later  stage  that  the 
residue  is  due  to  certain  metals  and  non-metals, 
always  present  in  the  crude,  commercial  zinc.  But 
let  us  return  to  the  bluish-green  liquid.  We  will 
evaporate  the  liquid  upon  a  water-bath  until  a  crust 
forms  over  the  surface,  which  signifies  the  beginning 
of  crystallization.  Then  we  set  it  away  over  night 
and  find  next  morning  a  crop  of  greenish  crystals. 
They  are  identical  in  form  with  the  vitriol  we 
started  our  experiments  with  ;  they  also  act  in  the 
closed  tube  in  the  same  way,  when  heated.  We 
have  thus  a  direct  proof  that  vitriol,  the  so-called 
copperas,  is  iron  vitriol.  Yet  when  we  take  the 
red  solid  residue  obtained  from  the  destructive  heat- 
ing of  the  copperas,  and  boil  that  body  with  sulfuric 
acid  and  trihydrate,  we  get  a  yellow  solution,  from 
which,  by  evaporation,  yellow,  scaly  crystals  are 
deposited.  This  is  an  undoubted  vitriol,  but  not 
copperas,  yet  containing  all  the  elements  of  the 
latter.  Hence  no  other  deduction  is  possible  than 
the  following :  There  must  be  two  oxyds  of  iron,  as 
we  found  a  red  and  a  black  oxyd  of  copper,  an  SO2 
and  an  SO3.  These  oxyds  are  presumably  FeO 
and  FeO2.  But  which  of  these  is  in  copperas,  and 
which  is  in  the  yellow  crystals  ?  A  very  neat  little 
process  of  inductive  reasoning  will  give  us  the  an- 
swer. It  has  been  observed  at  the  beginning  of  this 
chapter  that  when  a  solution  of  copperas  in  water 
stands  exposed  to  the  air,  a  yellow  film  will  form  at 


GREEN    VITRIOL    OR    COPPERAS.  59 

the  surface.  That  this  must  be  due  to  the  action  of 
oxygen,  because  in  azote,  no  such  film  comes  into 
being.  We  can  accelerate  the  forming  of  the  yellow 
precipitate  by  blowing  air  into  the  liquid.  If  we 
dissolve  this  yellow  solid  (after  separating  it  from 
the  liquid  by  filtration)  in  dilute  sulfuric  acid,  we 
get,  after  evaporation,  the  same  yellow  crystals  as 
we  did  from  the  red  oxyd  +  sulfuric  acid,  and  if  we 
heat  the  yellow  substance  (not  the  crystals)  we  get 
in  fact  the  red  oxyd.  Therefore  it  follows  that  cop- 
peras contains  the  lower  oxyd,  and  the  red  oxyd  is 
the  higher  oxyd.  Just  how  the  proportions  of  oxy- 
gen and  iron  stand  we  cannot,  now,  prove;  but  let 
us  assume  that  this  proportion  is  1/1  for  the  lower 
and  2/3  for  the  higher  oxyd.  Then  we  can  write 

Fe  +  H2O.S03  +  aq.  =  FeO.SO3  +  aq.  +  H2, 

but  we  can  explain,  even  now,  why  we  get  so  much 
SO2  in  the  earlier  stages  of  vitriol  distillation. 
Namely  :  SO3  we  saw  is  a  strong  oxidizing  agent, 
and  hence  *the  lower  iron  oxyd  changes  at  its  ex- 
pense into  the  higher  oxyd. 

2(FeO.S03)  +  7H20  +  heat  =  7H20  +  SO2  + 

SO3  +  Fe2O3. 

We  must  of  necessity  get  just  as  many  molecules  of 
SO2  as  we  can  get  of  the  more  useful  oil  forming  SO3. 

Practical  application  of  some  parts  of  the  lesson  of 
oil  of  vitriol.  1.  How  to  prepare,  on  occasion  of 
need,  sulfur  dioxyd  (SO2).  A  250  c.c.  flask  2  is 
filled  to  about  one-half  with  thin  lathe  chips  of  cop- 
per. The  stopper  funnel  1,  Fig.  27,  is  filled  with 


60 


CHEMISTRY    SIMPLIFIED. 


sulfuric  acid  monohydrate.  B  is  a  burner ;  4  a 
wash-tube  partly  filled  with  water  ;  5  a  drying  tube, 
one-fourth  filled  with  concentrated  sulfuric  acid,  and 
6  a  bulb  tube  filled  with  glass  beads  which  have 
been  moistened  with  concentrated  sulfuric  acid. 
Why?  Because  up  to  a  certain  point  we  have 


FIG.  27. 


found  an  extraordinary  attraction  of  this  acid  for 
moisture.  Now  if  the  acid  flows  from  1  into  #  upon 
the  chips,  while  heat  is  properly  applied,  a  stream 
of  pure  SO2  will  soon  displace  all  the  air  from  flask 
and  tubes,  so  that  presently  pure,  dry  gas  issues  from 
6  ready  for  any  desired  purpose.  When  dry  gas  is 
not  required,  the  tubes  5  and  6  are  left  out.  After  the 
chips  are  used  up,  the  flask  must  be  cleaned  out ;  it 
is  best  though  to  clean  it  out  immediately  after  the 


GREEN    VITRIOL    OR   COPPERAS.  61 

need  is  past,  because  the  vitriol  will  become  as  hard 
as  rock  and  the  flask  be  much  in  danger. 

2.  How  to  Generate  Hydrogen.  This  substance  is 
very  often  required,  and  in  large  quantities,  for 
filling  a  balloon,  for  instance.  For  small  quantities 
you  may  use  the  apparatus  just  preceding,  Fig.  27. 
The  flask  2  is  partly  filled  in  this  case  with  granu- 
lated zinc,  and  dilute  acid  is  fed  into  the  funnel  1. 
Make  the  acid  1:20,  that  is,  20  volumes  of  water 
for  one  volume  of  the  acid.  You  will  find  that 
such  a  simple  contrivance  is  all  right  for  a  small 
volume  of  gas,  but  not  for  more,  and  what  you  do 
get  comes  very  fast  at  first,  then  ever  slower.  Why? 
Because  the  dilute  acid  becomes  a  solution  of  zinc 
vitriol,  which  renders  the  acid  more  and  more  weak. 
Many  devices  have  been  designed  to  get  a  better 
result.  The  adjoining  figure,  Fig.  28,  shows  my 
own  design,  which  has  given  complete  satisfaction 
to  all  those  who  gave  it  an  intelligent  trial.  The 
principal  part  of  the  apparatus  is  a  glass  tube  G 
drawn  slightly  into  a  neck  N,  and  at  the  lower  end 
into  a  narrow  tube  0,  to  which  latter  is  fitted  a 
stout  rubber  tube  R.  The  latter  forms  a  U,  has  a 
glass  nozzle  P,  and  thus  discharges  the  dilute  solu- 
tion of  zinc  vitriol  into  the  glass  jar  TT.  This  tube 
G,  which  we  better  name  the  "  generator  "  is  filled 
with  the  granulated  zinc.  It  is  surrounded  by  a 
wider  tube  /  which  is  melted  at  both  ends  together 
with  the  generator,  thus  forming  a  jacket.  The 
latter  can  be  filled  with  water  through  the  tubula- 
ture  E.  The  function  of  the  jacket  is  to  keep  up  a 


62 


CHEMIbTRY   SIMPLIFIED. 
FIG.  28. 


B 


KOENIG'S  GENERATOR. 


GREEN    VITRIOL    OR    COPPERAS.  63 

temperature  of  about  70°  C.  in  the  generator.  To 
this  end  a  5-millimeter  glass  tube  t  has  been 
melted  into  the  jacket  obliquely.  The  middle 
portion  of  the  tube  is  of  brass  and  is  here  heated  by 
a  little  flame  which  burns  from  a  glass  tube  or  from 
a  Bunsen  burner.  A  rubber  stopper  closes  the  neck 
N  and  through  it  passes  the  funnel  tube  F  which 
should  be  12  inches  long.  The  whole  apparatus  is 
held  in  vertical  position  upon  two  brackets  which 
may  either  be  attached  to  a  portable  stand  Q  or  may 
be  put  against  the  wall  under  the  hood  permanently. 
The  zinc  is  prevented  from  falling  into  the  rubber 
tube  by  the  "  false  bottom  "  D  made  of  porcelain. 
After  the  jacket  has  become  hot  you  fill  the  bulb  of 
the  funnel  with  the  dilute  sulphuric  acid  1:20,  and 
also  fill  water  into  the  generator  until  it  begins  to 
run  from  the  nozzle  P.  Now  open  the  stopcock  of  the 
funnel  so  much  that  a  drop  falls  from  the  stem 
every  second,  and  soon  a  steady  stream  of  hydrogen 
will  issue  from  the  tubulature  L.  The  gas  will  be 
free  from  air  sooner  than  in  any  other  form  of 
generator.  The  gas  will  be  washed  and  dried  as 
shown  above.  When  the  column  of  zinc  has  fallen 
by  three  inches,  it  should  be  filled  up ;  but  that  in- 
cludes a  steady  running  for  a  whole  day.  For 
much  use,  a  large  reservoir  bottle,  holding  the 
dilute  acid,  should  be  rigged  up  above  the  funnel, 
so  that  the  acid  can  be  drawn  into  the  cup  of  the 
funnel  by  means  of  a  syphon. 


CHAPTER  IV. 

THE  LESSON  OF  LIMESTONE. 

WE  have  before  us  three  productions  of  nature, 
which  to  the  eye  are  very  different.  The  first  is  a 
large  crystal  of  dog-toothed  spar,  calcspar  or  cal- 
cite,  quite  common  in  our  copper  mines,  notably  at 
the  Quincy  Mine,  where  it  is  intimately  associated 
with  the  native  copper.  This  particular  crystal 
comes  from  the  zinc-lead  mines  of  Joplin,  S.  W. 
Missouri.  You  will  notice  that  one  end  of  the  crys- 
tal shows  three  lustrous  faces  intersecting  over  the 
edges  at  an  angle  of  a  hundred  and  five  degrees 
nearly — a  rhombohedron — whilst  the  other  end 
shows  six  faces  intersecting  at  alternately  different 
angles  —  a  scalenohedron  because  the  faces  are 
scalene  triangles — thus  producing  the  impression  of 
a  dog's  fang.  Parallel  to  the  faces  of  the  rhombo- 
hedron the  mineral  cleaves  perfectly.  I  cleave  off 
a  piece  and  you  see  a  small  rhombohedron  exactly 
similar  to  the  original  one.  It  is  both  colorless  and 
transparent,  and  if  placed  upon  this  cross  upon 
white  paper  we  see  the  lines  of  the  cross  double;  the 
two  images  are  close  together.  The  physicists  say 
the  mineral  has  double  refraction  and  give  you  an 
explanation  according  to  the  present  state  of  their 
knowledge.  From  this  property  the  mineral  is 

(64)   ' 


THE    LESSON    OF    LIMESTONE.  65 

sometimes  called  double-spar  (the  latter  word,  spar, 
is  given  to  all  minerals  which  are  more  or  less 
transparent  and  show  strong  cleavage). 

The  second  specimen  is  this  whitish  rock  which 
is  known  as  crystalline  limestone.  It  shows  num- 
bers of  small  but  splendent  faces,  each  of  which  is 
in  reality  the  face  of  a  rhombohedron  similar  to  that 
of  the  calcite  :  or  in  other  words  the  rock  is  made  up 
of  innumerable  calcite  rhombohedrons  which  pre- 
vented each  other  from  developing  individual  geo- 
metric independence. 

The  third  specimen  is  this  dull  gray  rock  com- 
monly known  as  limestone.  In  its  appearance  there 
is  nothing  in  common  with  the  previous  specimens. 
But  all  three  possess  nearly  the  same  relative  weight 
(specific  gravity),  and  an  equal  power  of  resistance 
to  a  penetrating  steel  point  (equal  hardness).  The 
comparison  thus  far  made  we  call  physical,  mean- 
ing therewith  that  all  the  given  properties  have 
been  ascertained  without  destroying  the  identity  of 
the  original  substance.  Let  us  now  act  upon  these 
materials  with  the  powerful  agents  in  our  posses- 
sion, whereby  the  original  identity  will  become 
modified  or  wholly  destroyed,  new  bodies  being 
produced.  The  knowledge  thus  gained  will  be 
chemical  knowledge,  and  will  greatly  widen  out  our 
horizon  as  to  the  nature  of  things. 

1.  Action  of   heat.      Place  a  fragment  of  calcite 

in  a  glass  tube  closed  at  one  end,  and  heat  this 

end  to  high  redness.    No  odor  ;  fragment  turns  dull 

chalky.     It  might  nevertheless  be  that  an  odorless 

5 


66 


CHEMISTRY    SIMPLIFIED. 


gas  is  evolved.  Contrive  a  rig  as  sketched  in  Fig. 
29,  wherein  t  is  the  hard  glass  tube  with  the  frag- 
ments. B  B  are  two  bricks  to  concentrate  and  re- 
flect the  heat  rays  upon  the  tube.  T  is  a  test-tube 
filled  with  water  and  t'  a  short  bent  glass  tube  at- 
tached to  t  by  a  short  piece  of  rubber  tubing.  The 
heat  may  be  produced  by  means  of  a  blast  lamp  or 
by  placing  over  the  tube  t  several  pieces  of  charcoal 
made  incandescent  and  by  then  fanning  them  into 
combustion  by  an  air  blast  or  by  means  of  an  ordi- 

FIG.  29. 


nary  fan.     The  heating  with  coal   is  much  more 
satisfactory  than  with  the  blast  lamp. 

When  the  tube  has  come  to  red  heat,  we  observe 
a  steady  current  of  gas  bubble  through  the  water 
into  the  test-tube.  The  gas  is  odorless  and  evi- 
dently not  soluble  in  water  to  any  considerable  ex- 
tent. Now  we  found  the  gas  from  the  copperas  to 
give  a  sour  taste  to  the  water,  aside  from  the  strong, 
pungent  odor ;  hence  we  examine  the  present  gas  in 
the  same  direction.  Water  is  not  changed  to  the 
taste  but  blue  litmus  paper  is  slightly  reddened. 
We  say  the  lime  gas  has  a  weak  acid  nature.  It 
does  not  burn  or  explode  as  hydrogen  and  does 


THE    LESSON    OF    LIMESTONE.  67 

not  stimulate  or  increase  a  burning  as  oxygen. 
It  is  of  all  gases  thus  far  encountered  most  like 
azote.  But  in  making  soap  bubbles  with  it,  the 
latter  immediately  fail  to  the  floor  ;  hence  the  gas 
must  be  much  heavier  than  air  or  azote  (the  latter 
being  -f  of  the  air)  and  moreover  azote  does  not  im- 
part sour  or  acid  properties  to  the  water.  Thus  we 
are  forced  to  the  conclusion  that  this  lime  gas  is  a 
new  body.  But  if  so,  we  ask,  is  it  a  simple  or  com- 
pound body  ?  In  order  to  find  answer  to  this  ques- 
tion, let  us  do  some  reasoning  by  comparison  :  The 
copperas  or  iron  vitriol  is  crystallized  or  transpar- 
ent ;  it  has  been  proven  to  be  composed  of  two 
oxides  +  water.  Calcite  is  crystallized  and  trans- 
parent, gives  off  a  slightly  acid  gas  and  leaves  a 
white  opaque  solid.  Hence  we  will  be  justified  in 
the  assumption  that  calcite  also  is  composed  of  two 
oxyds,  one  metallic,  the  other  non-metallic. 


This  is  an  hypothesis  (the  word  is  the  Greek  equiva- 
lent for  either  supposition  or  assumption). 

Proof  for  the  gaseous  or  volatile  part.  If  the  gas  be 
an  oxyd  like  water  (as  steam)  it  may  be  possible  to 
break  it  up  by  a  metal  such  as  zinc,  or,  as  we  saw 
with  the  oxyds  of  iron  and  copper,  heat  and  char- 
coal might  do  it.  Let  us  choose  zinc  in  the  form  of 
these  bright  chips.  It  will  be  necessary  to  produce 
a  small  but  steady  current  of  the  lime  gas.  Having 
seen  that  both  dilute  sulfuric  acid  and  vinegar  can 
decompose  the  calcite  and  the  limestone,  we  choose 


68 


CHEMISTRY    SIMPLIFIED. 


the  vinegar.  Why  ?  Because  the  latter  gives  a  so- 
luble product,  whilst  the  sulfuric  acid  gives  a  milky 
solution  or  a  white  mush,  an  insoluble  vitriol.  In 
the  flask  F  (Fig.  30)  bring  about  20  grams  of  finely 
ground  calcite  or  limestone  with  about  50  c.c.  of 
water.  Into  the  funnel  V  pour  concentrated  vine- 
gar acid,  acetic  acid,  because  the  Latin  word  for 
vinegar  is  acetum.  With  the  help  of  a  small 
flame  a  steady  current  of  gas  can  be  made  for  quite 


FIG.  30. 


V 


T 


s 


a  while,  admitting  more  acid  in  small  portions  as 
needed.  In  the  hard-glass  tube  T  at  Z  lay  the  zincj 
chips  between  two  asbestus  plugs.  The  flame  L 
will  bring  Z  to  red  heat.  Stand  S  with  clamp  K 
holds  T  in  position.  But  since  we  want  to  prove 
an  oxyd,  it  is  evident  that  such  proof  would  become 
impossible  if  the  gas  were  to  enter  T  at  once,  for  the 
gas  is  charged  with  water  vapor  and  we  know  that 
water  will  yield  oxyd  when  brought  together  with 
red-hot  zinc.  We  therefore  interpose  the  test-tube 
D  which  is  partly  filled  with  concentrated  sulfuric 


THE    LESSON    OF    LIMESTONE.  69 

acid,  through  which  the  gas  will  have  to  rise  in 
bubbles.  We  do  this  because  we  found  that  oil  of 
vitriol  absorbs  water  with  very  great  energy.  It  is 
a  dryer.  Had  we  not  observed  well  and  noted  this 
property  we  would  now  stand  before  an  impassable 
obstacle.  But  going  as  we  do,  the  discoveries  come 
apace  with  their  immediate  practical  application. 
Xow  we  begin  the  generation  of  the  gas.  The 
latter,  being  heavier  than  air,  forms  a  steadily 
thickening  layer  over  the  liquid  in  F,  driving  the 
air  before  it  and  out  of  the  entire  apparatus.  We 
keep  on  patiently  until  at  least  two  volumes  equal 
to  F  have  been  generated  to  make  quite  sure  that 
the  air  is  completely  displaced.  For  if  any  remain 
our  results  could  not  be  conclusive,  since  some  zinc 
oxyd  would  surely.be  formed,  whether  the  lime  gas 
were  an  oxyd  or  not.  Zinc  is  coming  to  redness ;  a 
white  cloud  appears  on  the  glass.  But  in  order  to 
find  what  becomes  of  the  gas  let  a  rubber  tube  be 
brought  under  a  test-tube  G  filled  with  water,  and 
it  will  be  seen  that  the  tube  soon  fills  with  a  color- 
less, inflammable  gas.  The  zinc  is  oxydized.  Now 
we  may  assume  that  the  inflammable  gas  is  the 
element  Y  or  a  lower  oxyd  of  Y  and  symbolize  thus : 

YPO  +  qZn  +  red  heat  =  YP  +  qZnO 
or 

YPO  +  Zn  +  red  heat  —  YPQ^1  +  ZnO. 

This  alternative  brings  us  up  against  the  wall  once 
more.  Unless  we  shall  happen  to  discover  a  metal 
with  greater  attraction  for  oxygen  than  the  zinc,  we 
shall  not  be  able  to  prove  directly  that  the  com- 


70  CHEMISTRY    SIMPLIFIED. 

bustible  gas  is  an  element  or  a  lower  oxyd.  Let  us 
not  despair  ;  of  wonders  and  signs  of  wonders  there 
is  no  end. 

Study  of  the  residuum.  In  order  that  this  residue 
may  be  as  much  freed  from  the  gas  as  possible,  let 
us  pour  it  from  the  glass  tube  into  this  platinum 
crucible.  This  latter  being  infusible  we  may  con- 
centrate upon  it  a  much  higher  heat  than  was  pos- 
sible in  the  glass  tube.  Lifting  the  lid  we  see  the 
pieces  emit  a  white  glow,  whilst  the  metal  of  the 
crucible  is  only  yellow.  We  say  the  lime  is  highly 
incandescent.  The  pieces  still  show  the  rhombo- 
hedrons  of  cleavage ;  there  is  even  luster  upon  the 
faces.  The  volume  is  the  same  but  the  weight  has 
decreased  44  per  centum.  Cohesion  has  decreased. 
This  residue  is  known  as  burnt  lime — caustic  lime 
("  caustic"  being  merely  the  Greek  for  burnt).  It  has 
been  known  for  ages  to  both  civilized  and  savage 
peoples.  Since  limestone  forms  the  surface  rock  for 
many  square  miles  in  large  tracts  of  country  all 
over  the  earth,  the  first  burnt  lime  was  made  when 
the  first  man — living  in  a  limestone  country — made 
a  rough  fireplace  with  the  pieces  of  rock  around 
him.  According  to  our  hypothesis  burnt  lime 
ought  to  be  an  oxyd  XnOm,  the  oxyd  of  a  metal  X 
whose  properties  we  do  not  know.  For  if  we  try 
upon  this  lime  the  same  agents  which  yielded  us 
the  metal  from  the  oxyds  of  iron  and  of  copper, 
namely  intense  heat  (by  the  blow-pipe)  and  char- 
coal, our  trial  will  end  in  failure  ;  the  white  mate- 
rial remains  quite  unchanged.  What  was  said  of 


THE    LESSON    OF    LIMESTONE.  71 

the  final  nature  of  the  element  Y  above,  applies 
here  in  regard  to  X.  Let  it  stand  for  the  present 
as  X,  or  since  we  called  Y  the  lime  gas,  let  X  be  the 
lime  metal  We  may  even  designate  by  the  symbol 
Ca  (the  first  letters  of  the  word  calcite),  since  we 
designate  iron  by  the  symbol  Fe  (the  first  letters  of 
the  word  ferrum)-,  yet  ever  bear  in  mind  that  it  is 
a  suppositions,  a  hypothetical  simple  body  of  whose 
properties,  in  the  first  state,  we  are  ignorant.  This 
ignorance  does  not  prevent  us  from  studying  the 
behavior,  the  properties  of  the  supposed  oxyd. 

First  towards  water.  Let  a  drop  of  water  fall  upon 
some  of  the  caustic  lime,  a  hissing  noise  ensues ;  a 
slight  cloud  of  steam  arises  ;  the  lime  swells  up  and 
falls  into  an  extremely  fine  powder :  Flour  of  lime. 
The  flour  can  be  dried  at  steam  heat  and  yet  this  dry 
flour  will  yield  water  in  the  closed  tube,  at  red  heat, 
and  lose  24.3  of  its  weight.  After  cooling  moisten 
the  lime  and  it  will  hiss  with  water  as  before  and 
fall  into  flour.  Hence  we  say  the  burnt  lime  has  a 
very  strong  affinity  for  water,  and  will  form  with 
it  a  true  union,  a  chemical  compound,  a  hydroxyd, 
very  much  as  the  sulfur  oxyd  SO  which  forms 
the  hydroxyd  we  called  sulfuric  acid.  Deduction  : 
Both  metallic  oxyds  and  non-metallic  oxyds  form  hy- 
droxyds. 

Flour  of  lime  =  lime  hydroxyd  =  CanOm.H20. 

Adding  more  water  the  lime  hydroxyd  turns  into 
a  white  paste :  Slaked  lime.  If  we  add  much  water, 
shake  and  stir  thoroughly  and  then  let  stand,  we 
notice  that  apparently  the  whole  of  the  white  paste 


72  CHEMISTRY    SIMPLIFIED. 

will  settle,  leaving  a  clear  liquid  above.  Deduc- 
tion :  Lime  hydroxyd  is  very  little — if  any — soluble 
in  water.  However,  the  water  has  a  decided  taste, 
and  turns  reddened  litmus  paper  to  blue.  Hence  it 
is  an  agent,  and  we  call  it  lime  water.  By  evaporat- 
ing 1*00  c.c.  in  a  weighed  dish,  we  obtain  a  residue 
of  hydroxyd  of  0.1  gram — 1000  lime  water  hold  1 
hydroxyd. 

Second,  towards  acids.     Make  a  -^  p.  c.  solution  of 
sulfuric  acid  and  of  vinegar  or  acetic  acid.     Because 
sulfuric  acid  has  a  specific  gravity  of  1.83,  we  will 
require  0.054  c.c.   to  give  us  0.1   gram  (1.83  :  1  = 
OJ   :  0.054),  that  is,  just  one  small  drop  for  the  100 
c.c.  of  water.     The  strongest  acetic  acid  has  sp.  grav. 
1.05,  nearly  the  same  as  water.     Two  small  drops 
of  it  will  give  the  strength  wanted  with  100  c.c.  of 
water.     Pour  25   c.c.  of  each   of  these  very  diluted 
acids  into  2  beaker  glasses,  add  a  little  litmus  solu- 
tion to  each,  which  will  produce  red  color.     Now 
slowly  add  clear  liine  water  from  a  graduate  into 
the   first  beaker  glass.     All  at  once  the  red  color 
changes  to  blue,  when  a  certain  number  of  c.c.  have 
been  added.     The  same  with  the  acetic  acid.     We 
deduce :  The  two  bodies  of  opposite  action  to  litmus 
saturate  each  other  so  that  a  neutral  body  results,  the . 
neutral  body  is  the  salt.     Let  M  stand  for  any  metal, 
and  N  for  any  non-metal,  then 
MnOm.H20  =  hydroxyd  =  base 
NnOm.H20  ==  hydroxyd  =  acid 
MnOm.H2O  -f  NnOm.H20  =  MnOm.NnOm  (salt)  -f 
2H20 


THE    LESSON    OF    LIMESTONE.  73 

The  three  conceptions  are  fundamental  in  chem- 
istry. Base,  acid,  salt.  Yet  neither  base  nor  acid 
is  to  be  understood  in  the  absolute  sense.  Two 
metallic  hydroxyds  may  act  as  base  and  acid 
towards  each  other,  or  in  other  words  one  is  more 
basic  than  another.  We  shall  find  examples  as  we 
proceed.  This  much,  however,  impress  upon  your 
mind :  An  oxyd  is  rarely  an  active  agent ;  in  order 
to  make  one  oxyd  act  upon  another  oxyd  strong 
external  impulse  is  needed,  such  impulses  being 
heat  and  electricity.  The  internal  activity  becomes 
manifest  towards  the  surroundings  with  the  forma- 
tion of  the  hydroxyd.  This  will  become  clearer  in 
the  next  chapter. 

Allow  a  portion  of  the  liquid,  in  which  you  have 
saturated  the  lime  hydroxyd  with  the  sulfuric  acid, 
to  evaporate  on  a  watch  crystal.  Groups  of  crystals 
will  be  formed,  colorless,  needle-shaped.  Examine 
them  with  a  microscope.  They  are  often  stellar, 
that  is,  radiating  from  a  centre.  When  heated 
these  crystals  will  loose  water  readily ;  they  are 
CaO.SO3  +  2H2O— a  vitriol  in  which  two  mole- 
cules of  loosely-bound  water  of  crystallization  are 
tacked  on  to  the  salt  proper  as  in  iron  vitriol  and 
copper  vitriol. 

Action  of  the  lime  gas  upon  the  lime  hydroxyd. — 
Lime  water  is  the  iV  per  cent,  solution  of  the  lime 
or  calcium  hydroxyd  in  water.  Generate  the  gas 
as  above  and  let  it  bubble  through  some  of  the  solu- 
tion in  a  test-tube  ;  a  turbidity  appears  at  once  which 
gradually  turns  to  a  milky  white  color  and  white 


74  CHEMISTRY    SIMPLIFIED. 

sediment.  Filter  this  upon  a  small  paper  filter, 
dry  it.  It  has  no  taste.  Heat  some  of  it  to  yellow 
heat  upon  a  bit  of  sheet-iron  (platinum  preferable 
but  too  costly) ;  after  cooling  transfer  it  to  a  slip  of 
reddened  litmus  paper  and  moisten  with  one  drop 
of  water.  Observe  that  it  slakes  and  the  litmus 
turns  blue  under  the  white  mass.  Place  another 
minute  quantity  of  dry  precipitate  upon  a  watch 
glass  or  plain  glass  slide  and  examine,  after  moisten- 
ing it,  with  a  high  power  of  the  microscope.  Minute 
but  perfect  transparent  rhombohedrons  appear. 
Hence  deduction  :  Lime  gas  converts  lime  hydroxyd 
into  calcite  from  which  we  started.  High  heat 
breaks  up  the  combination  of  the  two  oxyds ;  at  low 
heat  (temperature  of  room)  they  recornbine.  Con- 
clusion :  Very  high  heat  always  counteracts  the 
chemical  attraction,  tends  to  separate  the  minute 
mass-units.  Now  let  the  lime  gas  bubble  through 
another  portion  of  the  lime  water  and  leave  it  for 
some  time,  being  called  away.  On  returning  we  find 
the  original  rnilkiness  all  gone  ;  evidently  the  calcite 
has  been  dissolved  in  an  excess  of  gas.  Boil  the  clear 
solution  and  shortly  milkiness  as  well  as  sediment 
reappears.  Conclusion :  Boiling  heat  expells  the 
solving  excess  of  gas,  the  dissolved  calcite  being  it- 
self almost  insoluble  (one  part  in  250,000  parts 
water),  must  precipitate.  This  is  the  reason  why  the 
hard  water  of  limestone  regions  always  gives  a  sedi- 
ment after  boiling  and  the  boiled  water  becomes 
soft.  Here  is  some  lime  water  which  has  been 
standing  for  quite  a  while  in  the  open  beaker  glass. 


THE    LESSON    OF    LIMESTONE.  75 

Note  that  a  film  has  been  forming  on  the  surface. 
The  film  shows  iridescence  in  strong  sunlight.  Re- 
move some  to  a  glass  ^  slide  and  you  will  find  with 
a  high  power  the  identical  rhombohedrons.  De- 
duction :  If  calcite  forms  under  these  conditions  it 
is  evident  that  the  lime  gas  must  be  part  of  the 
atmosphere.  And  since  the  film  forms  much 
more  rapidly  in  a  crowded  room  than  outside, 
we  must  reason  that  lime  gas  forms  part  of  the 
effluvia  or  gaseous  emanations  of  the  human 
body.  Another  important  side-gain  is  that  the 
hardening  of  mortar  must  be  owing  to  the  absorp- 
tion by  the  slaked  lime  of  the  lime  gas  in  the  air. 
Mortar  is  a  mixture  of  80  to  85  parts  of  sharp  sand 
with  20  to  15  parts  of  quick-lime  in  the  slaked 
condition. 

All  the  actions  observed  are  identical  for  calcite, 
crystalline  limestone  and  common  limestone;  their 
substance  is  identical,  though  their  look  is  very 
different.  This  must  be  noticed,  however,  that  the 
gas  evolved  from  common  limestone  possesses  a  fetid 
odor  which  is  owing  to  oily  matter  often  contained 
in  the  limestone.  * 

Summary  of  limestone  lesson.  Discovery  of  a  gase- 
ous oxyd  whose  non-metal  Y  is  at  present  unknown. 
Of  a  metallic  oxyd  (probably)  whose  action  towards 
the  acids  is  equal  to  the  oxyds  of  iron  and  copper, 
though  we  do  not  know  the  metal  contained  therein. 
The  oxyd  differs  by  its  tendency  to  form  hydroxyd 
and  by  its  action  on  litmus  paper,  which  we  call 
basic  action. 


CHAPTER  V. 
THE  LESSON  OF  WOOD  ASHES. 

WE  have  before  us  the  familiar  and  homely 
material — ashes.  There  are  evidently  two  kinds. 
For  in  the  one  we  find  fragments  of  partly  coaled 
wood,  and  in  the  other  hard,  glassy  nodules  known 
as  clinkers.  The  first  is  the  remnant  from  burning 
wood,  the  second  the  remnant  from  burning  coal  in 
a  kitchen  range.  Why  should  I  bring  these  mate- 
rials before  you  ?  They  look  unpromising  enough. 
Because  I  find,  upon  trial,  that  the  wood  ashes  pro- 
duce a  strong,  biting  taste  similar  to  that  of  slaked 
lime,  whereas  the  coal  ashes  show  no  taste  what- 
ever. There  must  be  something  in  the  wood  ashes 
outside  of  the  ordinary  earth  calling  for  investiga- 
tion. The  Roman  historians  tell  us  that  when 
their  armies  came  in  contact  with  the  Teutonic 
tribes  on  the  Rhine,  they  found  it  a  custom  among 
these  for  the  women  to  do  up  their  hair  with  a  kind 
of  ointment,  and  this  they  made  up  from  fat  and 
wood  ashes.  It  was  indeed  what  later  on  was 
called  soft  soap.  Whilst  these  people  were  at  that 
time,  2,000  years  ago,  barbarians  much  like  the 
American  Indians,  they  had  the  spirit  of  investiga- 
tion stalking  among  them,  and  this  spirit  is  stalk- 
ing among  them  now.  When  linen  and  woolen 

(76) 


THE    LESSON    OF    WOOD    ASHES.  77 

cloths  had  superseded  the  skins  of  animals,  the 
original  hair  ointment  was  found  to  possess  excel- 
lent cleansing  properties ;  the  manufacture  of  soap 
became  a  separate  trade,  and  wood  ashes  came  to  be  an 
article  of  commerce.  The  early  pioneer  in  America, 
for  many  years,  had  nothing  to  exchange  for  grocer- 
ies and  other  store  goods  but  the  ashes  which  he 
collected  from  burning  out  his  clearings  in  the  for- 
est. However,  the  valuable  part  of  wood  ashes  is 
only  about  30  per  cent.;  the  storekeeper  had  no  use 
for  the  70  per  cent,  of  waste.  The  farmers  were 
made  to  extract  the  valuable  portion  with  hot 
water,  to  strain  the  liquid  through  canvas,  to  boil 
down  the  liquid  to  solidity,  in  iron  kettles  or  pots, 
hence  the  'commercial  product  came  to  be  called 
potash.  This  material  is  not  yet  pure ;  it  is  of 
brown  color,  and  contains  other  soluble  parts  of  the 
ashes.  It  undergoes  a  refining  process,  becomes 
white,  and  goes  under  the  name  of  pearl-ash.  How- 
ever, wood  has  become  so  scarce  everywhere  that  it 
can  no  longer  be  burnt  for  the  sake  of  the  ashes. 
How  means  were  found  to  replace  it  successfully,  in 
more  recent  times,  we  shall  see  in  a  following 
chapter. 

Investigation.  We  have  boiled  down  the  liquid — 
the  lye,  "  lie  "  (pronounce  lee)  in  French,  "  lauge  "  in 
German.  In  Germany  potash  was  called  "  laugen- 
salz  " — salt  made  from  the  lye. 

First  let  us  see  how  the  potash  acts  at  high  heat. 
We  place  some  in  a  hard -glass  tube  closed  at  one 
end.  First  some  water  condenses  in  the  upper  tube. 


78  CHEMISTRY    SIMPLIFIED. 

At  red  heat  the  substance  becomes  liquid,  and  then 
we  observe  small  gas  bubbles  arising  from  the  con- 
tact between  the  liquid  and  the  glass,  the  mo- 
bility is  changed  to  sluggish  flow.  Question : 
Have  the  escape  of  gas  bubbles  and  change  of  flow 
anything  to  do  with  an  action  upon  the  glass?  or 
is  it  inherent  in  the  potash  itself?  To  answer,  let 
the  glass  tube  be  substituted  by  a  metallic  vessel, 
say  an  iron  crucible.  The  potash  melts  as  before 
but  no  bubbles  come ;  the  liquidity  remains  the 
same.  It  follows  that  escape  of  gas  is  caused  by  in- 
teraction or  reaction  upon  the  glass.  Potash  is  fusi- 
ble at  red  heat  unchanged  :  remember  this  important 
fact. 

Act  with  sulfuric  acid  or  acetic  acid  upon  the 
dry  potash  and  upon  its  solution  in  water.  In 
either  case  there  is  strong  effervescence.  We  apply 
the  same  procedure  to  the  examination  of  the  gas 
which  we  used  with  the  lime  gas.  We  find  the  gas 
in  all  its  actions  like  the  lime  gas.  Moreover,  a 
white  granular  salt  falls  out  when  sulfuric  acid  de- 
composes the  potash,  a  vitriol.  Therefore  we  will 
be 'justified  in  the  assumption  that  potash  is  com- 
posed of  two  oxyds : 

PO.YnOm 

in  which  P  as  the  first  letter  of  potash,  stands  for  a 
metal  as  yet  unknown  to  us,  because  its  vitriol  is 
unlike  the  known  vitriols  in  its  crystal  form, 
unlike  also  as  to  solubility,  and  especially  unlike  in 
this,  that  heat  does  not  break  it  up ;  the  vitriol 
PO.SO3  stands  the  heat  of  the  blast-lamp,  as  I  here 


THE    LESSON    OF    WOOD    ASHES.  79 

show  you  in  the  glass  tube.  The  vitriol  is  more 
like  the  lime  vitriol  than  like  the  iron  and  copper  vit- 
riols ;  since  the  action  of  potash  and  lime  hydroxyd 
are  both  basic  to  litmus.  Since  heat  neither  breaks 
up  the  potash  nor  the  potash  vitriol,  how  shall  we 
get  at  the  hypothetical  oxyd  PO  ?  Let  us  reason  : 
We  found  calcite  insoluble,  but  convertible  into 
oxyd.  Suppose  we  bring  the  solution  of  potash 
together  with  the  lime  oxyd  in  this  test-tube,  and 
let  this  be  represented  by  the  scheme  : 
PO.YnOm  +  CaO  +  water. 

CaO  will  become  slaked  lime  with  the  water,  we 
will  then  get 

PO.YnOm  +  CaO.H20  +  water  +  boiling  heat. 
We  notice  turbidity  at  once,  then  flocculency,  then 
a  granular  precipitate.  We  filter.  The  filtrate  with 
sulfuric  acid  does  not  give  gas,  but  a  granular  salt 
falls  out  slowly  as  the  liquid  cools.  The  action 
must,  therefore,  have  been 


PO.H20  +  water 

the  non-metallic  oxyd  YnOm  has  gone  to  the  lime, 
and  only  the  hydroxyd  PO.H20  remains  in  solu- 
tion. The  filtrate  causes  deeper  action  on  the  skin 
of  the  fingers,  on  litmus  paper  and  on  the  tongue. 
It  also  follows  that  PO.H20  is  much  more  soluble 
in  water  than  CaO.H20. 

Potassium  hydroxyd,  caustic  potash,  caustic  potassa, 
potassium  hydrate.  The  first  of  these  names  I  want 
you  to  use.  The  second  and  third  names  are  older 


80  CHEMISTRY    SIMPLIFIED. 

and  still  used  in  the  drug  trade  ;  the  third  name  was 
the  current  scientific  name  and  is  used  by  the 
majority  at  present.  But  I  want  it  to  apply  to  a 
separate  conception.  To  make  myself  clearly  un- 
derstood we  will  return  to  the  action  of  water  upon 
oil  of  vitriol.  Represented  symbolically  we  have 
there  to  start  with  : 

H2O.SOa.nSO*. 

Adding  water,  little  by  little,  there  is  much  heat, 
also  hissing  noise,  this  lasting  until  the  nSO3  have 
combined  with  nH20  and  we  have  now  only 

H2O.S03 

our  concentrated  sulfuric  acid — the  true  hydroxyd. 
But  when  you  add  to  this  more  water,  both  being 
at  ordinary  temperature — the  liquid  warms  up  and 
can  even  reach  boiling  heat.  This  heat  means 
more  chemical  union  and  may  be  scheduled 

1st  hydrate  H2O.S03.H20 
2d  hydrate  H2O.S03.2H20 
3d  hydrate  HaO.S08.3H80 

nth  hydrate  H2O.S03.nH20 
and  similarly : 

H2O.PO  =  hydroxyd 
1st  hydrate  H2O.PO.H20 
2d  hydrate  H2O.P0.2H20 

nth  hydrate  H2O.PO.nH20 
The  nth  hydrate  may  be,  in  fact,  what  we  would 


^  THE    LESSON    OF    WOOD    ASHES.  81 

otherwise  designate  a  dilute  water  solution  of  the  hy- 
droxyd.  Returning  to  the  matter  immediately 
before  us,  we  evaporate  the  water  solution  of 
H2O.PO  to  dryness  in  an  iron,  copper  or  silver  dish. 
Glass  and  porcelain  are  strongly  attacked.  Prove 
this  statement  by  using  a  small  beaker  glass  and  a 
porcelain  crucible  ;  they  are  not  destroyed  but  lose 
the  lustrous  surface  and  some  of  their  material 
enters  the  liquid.  After  the  mass  has  become  dry 
at  boiling-point  of  water,  heat  over  an  open  flame. 
Soon  fluidity  will  occur,  more  steam  will  be  given 
off;  at  red  heat  white  vapors  appear  and,  using  a 
small  portion,  it  will  slowly  disappear  :  the  hydroxyd 
is  volatile  at  red  heat.  But  how  do  we  know  that 
this  material  is  hydroxyd  still ;  why  is  it  not  the 
oxyd,  when  the  lime  hydroxyd  looses  its  water  so 
readily  at  red  heat  ?  Revolving  in  our  minds  all 
the  actions  heretofore  performed,  we  remember  that 
both  iron  and  zinc  decompose  water  at  red  heat ;  it 
may  even  do  so  when  the  water  is  united  strongly 
to  another  oxyd.  The  rig  will  be  simple.  A  short 
piece  of  hard-glass,  thick-walled  tubing  closed 
at  one  end ;  a  perforated  stopper,  a  narrow  tube 
drawn  into  a  fine  opening  and  inserted  into  the 
stopper  will  probably  suffice.  We  introduce  a  piece 
of  the  problematic  hydroxyd  with  some  zinc  shav- 
ings, insert  the  stopper,  hold  the  tube  by  means  of 
a  clamp  in  inclined  position  and  apply  heat.  With 
the  melting  of  the  hydroxyd,  gas  bubbles  appear, 
and  ere  long  the  mass  will  want  to  froth  out  of  the 
tube,  the  escaping  gas  burns,  the  flame  deposits 
6 


82  CHEMISTRY    SIMPLIFIED. 

drops  of  water  against  a  cold  dish — the  gas  is  hy- 
drogen. In  symbols  the  action  is 

PO.H20  +  Zn  +  heat  ==  PO.ZnO  +  H2. 

After  cooling  we  find  that  the  mass  is  quite  soluble  in 
water,  all  but  some  remaining  zinc  chips.  Here  is 
one  example  of  two  metallic  oxyds  combining  to 
form  a  salt,  because  one,  PO,  is  more  basic  than  the 
other,  ZnO.  Thus,  whilst  proving  the  hydroxyd, 
we  have  incidentally  discovered  that  this  latter  is  a 
most  powerful  agent,  rivalling  the  sulfur  hydroxyd. 
It  corrodes  the  skin  rapidly ;  it  destroys  paper  and 
sawdust ;  it  dissolves  wool  and  hair,  horn  chips  and 
many  other  bodies.  In  these  actions  many  interest- 
ing and  useful  new 'substances  are  formed,  some  of 
which  we  will  inquire  into  hereafter.  We  find  our- 
selves now  in  possession  of  the  two  most  powerful 
agents  H2O.S03  and  PO.H20.  Acting  upon  each 
other  they  produce  the  neutral  vitriol  PO.SO3  and 
water.  Acting  separately,  they  lend  us  their  latent 
power. 

Action  of  calcite,  of  potash,  of  lime  hydroxyd,  of 
potassium  hydroxyd  and  their  hydrates  upon  the  water- 
soluble  vitriols  of  iron,  zinc,  copper.  The  vitriols  are 
in  dilute  solution  (you). 

1.  CaO.YnOm+  CuO.SO3  +  boiling  heat,  escape  of 

gas,  green  precipitate. 
+  FeO.SO3,   slight   brownish  precipi- 
tate. 
+  ZnO. SO3,  no  precipitate. 


THE    LESSON    OF    WOOD    ASHES. 

2.  PO.YnOm  +  CuO.SO3,  at  ord.  temp,  blue  precip., 

at  boiling  turns  black, 
-f-  FeO.SO3,  at  ord.  temp,  light  precip., 

at  boiling  turns  dark. 
-f  ZnO.SO3,  at  ord.  temp,  white  precip., 

at  boiling  remains  white. 

3.  CaO.H20  -f  CuO.SO3,  precipitate  at  ord.  temp. 

and  complete  at  boiling  heat. 
+  FeO.SO3,  precipitate  at  ord.  temp. 

and  complete  at  boiling  heat. 
+  ZnO.SO3,  precipitate  at  ord.  temp. 

and  complete  at  boiling  heat. 

4.  PO.H20    -h  CuO.SO3,  first  blue  precipitate  which 

turns  black. 
+  FeO.SO3,     light    green    precipitate 

which  turns  black. 
+  ZnO.SO3,    white    precipitate  which 

dissolves  in  excess. 

It  can  easily  be  proved  that  the  precipitates  formed 
under  (2)  are  the  combinations  of  CuO,  FeO,  ZnO 
with  YnOm,  whilst  the  PO  combines  with  SO3. 
CuO.  YnOm  turns  black  on  boiling,  because  the  CuO  is 
not  very  basic  and  cannot  hold  on  to  the  non  metal- 
lic oxyd  when  the  shattering  power  of  heat-waves 
pounds  upon  the  compound.  The  same  is  to  be 
said  about  CuO.H20  under  (4)  the  CuO  cannot  hold 
on  to  the  H20.  The  white  precipitate  (4)  in  zinc 
solution — ZnO. IPO  dissolves  in  excess  of  the  agent 
because  the  soluble  salt  PO.ZnO  forms,  thus 
First :  ZnO.SO3  -f  PO.H20=ZnO.H20-hPO.S03. 
Second:  ZnO.H20+PO.H20= PO.ZnO  +  2H20. 


84  CHEMISTRY    SIMPLIFIED. 

Of  iron  there  are  two  vitriols — a  green  and  a  yellow, 
the  latter  produced  by  acting  upon  iron  with  the 
hydroxyd  H2O.SO3  when  SO2  escapes  instead  of 
hydrogen. 

The  green  vitriol  contains  the  oxyd  FeO,  the 
yellow  vitriol  contains  the  oxyd  Fe203.  The  two 
vitriols  act  differently  on  our  four  agents.  But  the 
one  important  action  is  that  of  calcite  for  FeO.SO3-}- 
water  -f  CaO.YnOm  =  no  precipitate. 

Fe203.3S03  +  water-fCaO.YnOm  =  brown  precipi- 
tate, the  action  being  slow  at  ordinary  temperatures, 
rapid  when  heat  is  applied.  Hence  we  have  here  a 
means  of  separation  for  the  two  oxyds  of  the  same 
metal.  (Details  for  this  in  the  Chemistry  of  the 
Metals.)  Likewise  if  the  vitriols  of  Cu,  Fe,  Zn  were 
mixed  together  (the  iron  vitriol  being  of  the  green 
kind),  we  would  be  able  to  separate  the  oxyds — for 
(Cu  and  Zn)  vitriols  precipitate  by  calcite  or  chalk 
and  heat,  separating  the  iron.  The  precipitate 
boiled  with  PO.H20  will  leave  the  CuO  as  a  solid 
and  take  the  ZnO  in  solution.  Our  wealth  is  in- 
creasing as  we  go  along. 

The  metal  potassium.  Having  seen  that  the  oxyd 
PO  is  not  obtainable,  but  only  the  hydroxyd 
H2O.PO,  and  that  this  latter  is  quite  volatile,  their 
remains  only  one  raw  material,  the  potash.  Though 
it  be  a  salt,  the  peculiar  nature  of  its  non-metallic 
ox}^d  makes  it  possible  to  be  broken  up  by  coal,  at 
a  white  heat.  Cut  a  piece  of  f  "  or  V  gas  pipe  P 
(Fig.  31)  six  inches  long,  fit  on  a  cap  C}  an  elbow 
E  and  a  pipe  R  of  same  length,  all  joined  by  thread. 


THE    LESSON    OF    WOOD    ASHES.  85 

Fill  P  with  a  mixture  of  charcoal-coated  iron  chips, 
30  grams  of  fused  potash,  10  grams  of  burnt  lime. 
Screw  on  E  and  R  and  set  into  furnace  F.  The 
latter  is  heated  with  gasoline  burner  B,  but  a  good 
wind  furnace  and  coke  will  give  a  suitable  heat  also. 
In  order  to  prevent  the  pipe  from  burning  through, 
it  is  well  to  coat  it  over  with  several  coats  of  char- 
motte  or  braise,  a  mixture  of  three  parts  of  ground 
brick  and  one  part  of  fat  fire-clay.  The  pipe  R 

FIG.  31. 


is  kept  cool  by  a  wrapping  of  blotting  paper  upon 
which  water  drops  from  the  hydrant  or  spigot. 
A  cork  stopper  5  with  glass  tube  permits  the  gases 
to  escape.  The  burnt  lime  was  added  to  the  charge 
to  make  the  potash  less  fusible  ;  the  iron  to  hold  the 
charcoal  down,  preventing  it  from  floating  to  the 
top.  This  charcoal-coated  iron  is  made  by  heating 
iron  chips  and  sugar  together  in  a  covered  crucible 
until  no  more  gases  escape.  After  yellow  heat  has 
been  reached,  combustible  gas  will  appear  and  burn 


86  CHEMISTRY    SIMPLIFIED. 

at  5  with  either  a  purplish  or  yellow  flame.  Keep  up 
the  fire  for  an  hour,  then  cool  down.  A  gray  and 
black  loose  mass  will  be  found  in  R  If  some  be 
thrown  into  water  a  hissing  will  be  heard  and  for  a 
short  time  a  fine  purple  flame.  The  black  material 
is  a  mixture  of  small  metallic  pellets  and  a  spongy 
substance.  By  returning  this  mass  to  a  smaller 
apparatus,  of  exactly  the  same  form,  the  metal  can 
be  distilled  from  the  sponge  and  appears  then  almost 
pure  in  E.  The  electric  current  also  decomposes  the 
hydroxyd  PO.H20  thus :  The  metal  deposits  on  the 

FIG.  32. 


negative  pole  (cathode)  whilst  hydrogen  forms  at  the 
same  pole  and  oxygen  escapes  at  the  positive  pole. 

PO.IPO  +  current  =  P  -f  H2,  -f  O2 
It  is  difficult  to  keep  the  metal  from  burning  up 
again  in  presence  of  the  oxygen  surrounding  it. 
The  difficulty  may  be  avoided  by  pouring  some 
mercury  into  the  crucible  (Fig.  32)  and  some  of  the 
third  potassium  hydrate  over  it.  If  now  the  cruci- 


THE  LESSON  OF  WOOD  ASHES.          87 

ble  be  made  the  negative  pole  and  the  positive  pole 
be  a  platinum  wire,  the  metal  potassium  in  the 
moment  of  liberation  combines  with  the  mercury, 
alloys  with  it,  and  thus  is  kept  from  the  air.  The 
product  is  the  potassium  amalgam  HgnPm.  We 
place  the  latter  in  a  small  glass  retort  and  distill 
off  the  mercury  at  300°  C.  Potassium  remains  as  a 
liquid.  At  a  red  heat  it  also  becomes  volatile  and 
will  fill  the  flask  as  a  fine  green  vapor.  The  retort 
must  be  kept  filled  with  hydrogen  to  keep  out  the 
oxygen  of  the  air. 

Physical  properties  of  the  metal.  Potassium  has 
a  silver-white  color,  strong  metallic  lustre.  But  in 
presence  of  air  tarnishes  at  once,  becoming  covered 
with  a  gray  film.  Therefore,  the  metal  must  be  kept 
under  a  liquid  which  does  not  contain  oxygen — such 
as  kerosene.  The  metal  is  soft,  like  fresh  putty  at  or- 
dinary temperature,  becomes  brittle  below  the  freez- 
ing point ;  that  means  it  crystallizes,  appearing  in 
tetragonal  pyramids.  It  melts  at  62.5°  C.;  at  red 
heat,  730°  C.,  the  liquid  boils  like  water;  the  vapor 
is  green.  Its  specific  gravity  is  0.865  (water  1), 
hence,  it  floats  on  water,  but  sinks  in  kerosene,  sp. 
gr.  0.76  —  0.78.  The  specific  heat  or  heat  capacity 
is  0.166  (water  =  1). 

Chemical  properties.  Potassium  decomposes  water 
with  great  energy,  because  of  all  metals  it  has  the 
strongest  affinity  for  oxygen. 

p  +  H20  ==PO  +  H2 

but  since  an  attraction  exists  between  the  oxyd  and 
the  water  the  action  really  is 


88 


CHEMISTRY    SIMPLIFIED. 


P  +  2H20  =  PO.IPO  +  H2. 

For  instance,  if  you  wish  to  ignite  coal-oil  which 
floats  on  water,  you  would  just  throw  a  piece  of 
potassium  on  the  water,  and  the  oil  would  be  on  fire 
at  once. 

I  said  potassium  had  the  strongest  attraction  for 
oxygen  of  any  metal.  Why,  then,  were  we  able  to 
dislodge  it  by  iron  and  by  charcoal  ?  The  answer 
is  found  in  that  potassium  is  so  easily  volatilized*. 
We  could  not  separate  the  calcium  from  the  lime 
oxyd,  because  the  calcium  is  not  volatile. 

Proof  of  the  nature  of  the  unknown  Y  in  lime  gas. 
Once  in  possession  of  potassium,  we  will  try  it  upon 
the  lime  gas,  which  zinc  only  changed  into  com- 
bustible gas  (see  above),  and  of  which  we  remained 

FIG.  33. 


doubtful  whether  it  was  Y  or  a  lower  oxyd  of  Y. 
Let  the  lime  gas  be  generated  from  calcite,  chalk, 
or  limestone  by  means  of  the  acetic  acid  as  before. 
Let  the  gas  bubble  slowly  through  H2O.S03,  Fig. 
33,  thence  pass  it  into  the  combustion-tube  t,  in 


THE    LESSON    OP   WOOD    ASHES.  89 

which  a  piece  of  potassium  has  been  placed  at  P. 
If  the  dish  D  contains  the  6th  potassium  hydrate, 
as  also  the  test-tube  t,  then  there  will  be  perfect 
absorption  of  the  gas  as  soon  as  all  the  air  is  ex- 
pelled from  the  apparatus  ;  because  we  know  that 
the  potassium  hydroxyd  as  well  as  the  different 
hydrates,  absorbs  the  gas  energetically  in  order  to 
become  potash  PO.YnOm.  Now  let  the  potassium  be 
heated  with  the  lamp  L.  It  melts,  spreading  over 
the  glass  and  forming  a  perfect  metallic  mirror. 
Then  it  ignites  and  burns  with  the  characteristic 
purple  flame  almost  the  same  as  in  air,  a  white 
smoke  developing.  Soon  the  potassium  becomes 
incrusted  with  a  white  material  and  a  black 
material.  All  the  gas  becomes  absorbed  for  a  while, 
then  reappears  in  the  tube  t.  This  designates  the 
end  of  the  action.  After  cooling,  we  remove  the 
mass  from  the  tube.  The  white  portion  gives  all 
the  actions  of  potash  :  Strong,  bitter  taste,  easily 
soluble  in  water,  and  gas  evolution  with  acid.  The 
black  portion  is  not  soluble  in  water ;  we  separate  it 
by  filtration.  It  looks  like  lamp-black  or  soot. 
Under  the  microscope  we  find  it  to  be  of  brown  color 
and  translucent  with  yellow  or  brown  color.  At 
red  heat  it  burns  and  disappears.  If  the  burning 
be  done  in  an  open  tube,  one  end  leading  by  rubber 
tube  into  lime  water,  Fig.  34,  and  air  being  sucked 
through  by  means  of  an  aspirator,  then  the  lime 
water  will  become  milky  ;  the  white  sediment  being 
rhombohedrons.  Hence  we  deduce  that  the  black 
substance  is  the  Y  in  the  lime-gas,  because  from  it 


90 


CHEMISTRY    SIMPLIFIED. 


comes  lime-gas  by  combustion.  Now  we  have  many 
times  observed  that  charcoal  burns  and  disappears, 
leaving  a  slight  residue  of  ashes,  and  we  naturally 
will  ask  :  Is  there  a  communion  between  the  black 
1 Y  and  charcoal  ?  To  satisfy  the  query  we  place  a 
splinter  of  charcoal  in  the  tube  T,  and  fresh  lime 
water  in  the  test-tube.  As  the  charcoal  burns,  the 
lime  water  becomes  milky  with  calcite.  Hence  we 


FIG.  34. 


Tl 


air 


/JME    W/ 


will  make  the  deduction  that  charcoal  is  either 
wholly  or  partly  made  up  of  the  black  substance  Y, 
and  we  resolve  the  Y  into  C,  which  is  the  first  letter 
of  the  Latin  word  carbo,  the  equivalent  of  the  Eng- 
lish charcoal.  With  characteristic  inconsequence 
the  English  language  makes  carbon  out  of  carbo. 
Our  lime-gas  becomes  now  CnOm;  the  calcite  becomes 
CaO.CnOm;  potash  PO.CnOm,  pronounced  calcium  car- 
bonate, and  potassium  carbonate. 

The  symbol  for  potassium  should  be  P  as  we 
adopted  it.  But  here  again  the  English  chemists 
are  inconsequent  in  choosing  K,  which  is  the  first 
letter  of  the  Arab  word  kali,  which  means  "burnt," 
but  was  given  by  the  Arab  chemist  Geber  to  our 
potash.  This  word  was  taken  up  by  all  chemists 


THE    LESSON    OF    WOOD    ASHES.  "91 

with  the  Arab  prefix  "  al,"  i.  e.,  alkali,  to  mean 
any  body  which  shows  the  essential  action  of 
potash,  these  actions  being  called  alkaline  actions. 
A  solution  is  said  to  be  "  alkaline  "  when  it  turns  red 
litmus  to  blue.  German  and  Swedish  chemists  call 
the  metal  potassium  kalium,  English,  American, 
and  French  chemists  stick  to  potassium,  but  they 
accept  the  symbol  K. 


CHAPTER  VI. 
THE  LESSON  OF  COMMON  SALT. 

COMMON  salt  is  before  us  in  three  forms.  1. 
Rock  salt  as  mined  at  the  mouth  of  the  Mississippi, 
in  Canada,  and  other  places  in  America.  It  is 
beautifully  transparent ;  colorless  or  colored,  some- 
times intensely  blue.  It  is  found  as  large,  perfect 
cubic  crystals,  and  again  as  immense,  solid,  irregu- 
larly shaped  masses  like  ice ;  or  as  fine  grained, 
snow-white  or  dirty  gray,  or  yellow,  or  red  masses. 
It  cleaves  perfectly  in  three  directions  at  right 
angles — cubical  cleavage.  It  presents  slight  re- 
sistance to  the  knife  or  to  the  drill.  It  has  a 
strong  taste  ;  is  readily  dissolved  by  water.  2.  Salt 
from  evaporation  of  salt  springs  and  salt  wells,  in 
snow-white  cubic  crystals,  which  are  all  hollow  on 
the  faces.  3.  Salt  from  evaporation  of  sea-water. 
It  is  certain  that  all  the  deposits  of  salt,  found  in 
nearly  all  geological  formations,  were  at  one  time 
dissolved  in  the  sea.  It  is  likewise  certain  that  salt 
springs  and  wells  dissolve  the  rock  salt  they  find  in 
the  rocks,  so  that,  in  the  end,  our  three  kinds  of  salt 
are  practically  only  one  kind,  sea-salt.  Man  and 
animals  crave  salt,  their  bodies  must  have  salt  or 
die.  Hence  all  the  languages  derived  from  some 
primitive  language  have  nearly  the  same  name  for 

(92) 


THE    LESSON   OF    COMMON    SALT.  93 

the  substance :  Greek :  hal,  Latin  :  sal,  French : 
sel,  German :  salz,  English :  salt.  The  plant-eating 
animals  get  some  salt  with  the  grass  and  leaves, 
but  it  is  known  that  they  will  travel  100  miles  and 
more  to  get  a  salt  spring  or  salt-lick,  to  satisfy  the 
craving  for  salt.  Carnivorous  animals  get  their  salt 
in  the  blood  of  the  grass-eaters  on  which  they  prey. 
Man  takes  his  from  both  plants  and  herbivorous 
animals.  Bloody  wars  have  been  fought  for  the 
possession  of  a  salt  spring  or  salt  mountain. 

The  United  States  are  well  supplied  with  salt, 
and  need  not  go  to  the  evaporation  of  sea-water. 
Germany  is  very  rich  in  salt ;  exports  much  to 
other  less  favored  nations.  Where  the  sun's  heat 
can  be  made  use  of  for  evaporation,  the  sea-water 
gives  very  cheap  salt. 

Investigation.  Heat  does  not  break  up  the  salt. 
Holding  a  piece  of  salt  in  the  flame  we  see  that  it 
melts  quickly  and  colors  the  flame  a  deep  orange- 
yellow.  Heating  the  salt  in  a  glass  tube  we  notice 
decrepitation  (enclosed  mother  liquor  escaping  ex- 
plosively), then  a  slight  water  condensation,  then 
melting,  then  boiling  and  forming  of  a  white  sub- 
limate. No  odor,  nor  gas. 

The  sublimate  shows  itself  made  up  of  cubic 
crystals,  tastes  and  acts  the  same  as  the  original 
salt.  Deduction :  Salt  is  volatile  without  decom- 
position. It  may  be  a  simple  body  as  far  as  heat 
action  shows.  But  not  so  by  its  behavior  towards  elec- 
tricity. We  place  salt  upon  a  platinum  crucible  lid, 
the  lid  being  in  contact  with  a  sheet  of  copper  and  the 


94  CHEMISTRY    SIMPLIFIED. 

latter  forming  the  positive  pole  of  the  current  As 
soon  as  we  bring  the  other  pole  wire  in  contact  with 
the  salt,  the  salt  melts  and  an  evolution  of  gas  ensues 
accompanied  by  a  very  strong  and  peculiar  odor. 
The  same  odor  is  produced  if  we  mix  salt  with  blue 
vitriol  and  heat  in  closed  tube.  But  let  us  try  our 
two  strong  agents  :  Sulfur  hydroxyd  and  potassium 
hydroxyd. 

SaltH-KO.H2O+heat=no  gas,  no  apparent  effect. 

Salt-|- H 2 O.SO 3 + heat— copious  evol ution  of  color- 
less gas  possessing  a  strong,  pungent  odor,  and  redden- 
ing blue  litmus.  Let  this  gas  be  called  salt-gas.  We 
let  the  gas  pass  into  water :  it  is  absorbed  eagerly, 
the  solution  becoming  warm.  Looking  at  this 
phenomenon  we  cannot  deny  that  it  is  similar  to 
the  action  of  IPO. SO3  upon  calcite,  hence  that  salt 
must  be  composed  of  two  oxyds 
MSO.NS0. 

in  which  neither  the  metal  M  nor  the  non-metal 
N  is  known  to  us.  With  this  supposition  as  a 
guiding  thread,  we  proceed  with  experiments  until 
we  shall  have  established  the  truth  or  falsity  of  the 
conception,  and  recognized  the  properties  of  both 
M  and  N. 

Salt  gas,  spirits  of  salt.     If  our  assumption  be  true, 
the  production  of  salt  gas  must  occur  thus 

MSO.NS0  +  IPO.SO3  =  IPO.NS0  +  MSO.S03 

the  salt  gas  must  be  the  hydroxyd  of  the  non-metal 
oxyd  NS0.  The  gas  contains  hydrogen.  For  if  we 
expose  zinc  to  it  hydrogen  is  evolved  at  once.  Let 


THE    LESSON    OF    COMMON    SALT. 


95 


F  be  a  flask  holding  about  500  c.c.  Let  it  be  fitted 
as  in  Fig.  35,  with  funnel,  stopper  and  escape  tube, 
all  standing  on  a  tripod  so  that  heat  may  be  applied. 
Let  C  be  a  bulb  tube  filled  with  cotton,  to  retain 
any  particles  carried  over  by  the  gas.  T  is  a  hard- 
glass  tube  with  two  perforated  stoppers.  B  a  bulb 
tube  providing  for  any  liquid  mounting  back  from 
D.  t  is  a  test-tube  to  receive  any  gas  which  may  be 

FIG.  35. 


generated.  Remove  stopper  /S',  introduce  50  grams  of 
salt  into  Fat  S,  fill  funnel  with  H2O.S03  and  drop 
the  latter  slowly  into  F  for  some  time,  until  upon 
•adjusting  S'  the  gas  bubbles  are  all  absorbed  in  the 
water  in  dish  D.  Open  at  S'  and  introduce  zinc  at 
Z.  Close  8'  and  adjust  tube  t.  The  speed  of  gen- 
eration of  the  gas  is  to  be  judged  by  the  frothing  of 
the  salt.  T  being  cold  (flame  L  not  having  been 
lit)  at  start,  will  now  warm  up :  zinc  decomposes 


96  CHEMISTRY    SIMPLIFIED. 

gas  at  ordinary  temperature,  the  combination  pro- 
duces heat.  Prove  the  gas  in  test-tube  is  hydrogen 
by  showing  it  inflammable.  At  Z  a  new  body  has 
been  formed  which  is  fusible,  proven  by  means  of 
lamp  L.  By  withdrawing  it  from  the  tube  it  is  found 
to  be  soluble  in  water.  (Prove  solution  by  testing 
with  potash  and  also  with  KO.H20),  therefore  this 
substance  cannot  be  zinc  oxyd  for  this  latter  is  neither 
fusible  nor  soluble  in  water;  it  must  be  a  combination 
of  zinc  with  the  unknown  N.  Acting  upon  it  with 
IPO.  SO3  the  pungent  gas  forms  same  as  with  the 
salt.  Nevertheless  the  combination  may  contain 
oxygen.  As  we  know  the  great  avidity  of  potassium 
for  oxygen,  let  us  act  as  follows  :  We  bring  into  a 
test-tube  a  part  of  the  unknown  compound  ZnNsO  ; 
we  fill  the  tube  with  hydrogen,  excluding  thus  any 
air ;  we  then  add  a  piece  of  bright,  carefully  cleaned 
potassium  and  apply  heat,  hydrogen  still  passing  in. 
The  action  would  have  to  be  thus  : 

ZnNsO  +  2K  +  heat  =  Zn  +  NSK  +  KO 

or  =  ZnKN8  +  KO 
or  with  3K  =  ZnK-f-NsK  +  KO 

It  will  evidently  not  matter  which  of  the  reactions 
ensues,  or  whether  all  three  occur  at  the  same  time. 
The  essential  point  is  the  forming  of  KO  ;  because 
if  water  be  now  brought  into  contact  with  the  mass, 
EPO.KO  will  be  formed  arid  will  cause  the  change 
in  litmus  from  red  to  blue.  The  experiment  will 
give  true  information  only,  if  ZnN80  be  in  excess, 
for  otherwise  K  would  be  left  and  in  contact  with 


THE    LESSON    OF    COMMON    SALT.  97 

water  would  give  the  hydroxyd  -f-  hydrogen.  The 
experiment  must  be  made  with  much  judicious  care, 
and  will  prove  that  KO  is  not  formed  and,  hence, 
that  oxygen  is  not  present  in  the  compound  and  there- 
fore not  present  in  the  salt  gas.  Our  preliminary  sup- 
position was  wrong  :  Salt  gas  must  be  NSH.  How  are 
we  to  set  free  Ns  ?  In  the  case  of  the  limestone  gas  we 
were  successful  with  potassium  because  the  C  (carbon) 
does  not  combine  with  potassium  ;  but  in  this  in- 
stance, when  we  find  the  unknown  Ns  to  combine 
with  zinc,  it  seems  more  than  likely  that  it  will 
combine  with  potassium  also.  However,  let  the 
trial  be  made.  The  apparatus,  Fig.  35,  will  be 
quite  suitable.  We  simply  substitute  a  piece  of 
potassium  at  Z  in  place  of  zinc.  We  note  a  strong 
action  even  at  ordinary  temperature,  a  white  sub- 
stance forming  and  hydrogen  evolving.  The  white 
substance  forms  cubes  and  octahedrons,  it  tastes  like 
common  salt  ;  hence  we  conclude  that  the  metal 
M  in  salt  must  be  similar  in  its  nature  to  K.  Whilst 
this  is  welcome  information,  it  is  not  what  we  are 
looking  for.  The  unknown  is  not  set  free. 

Another  train  of  thought  is  needed  ;  we  know  the 
unknown  to  be  a  hydrogen  combination.  Now  the 
metals  having  failed  us,  let  us  try  the  non-metals. 
Of  these  we  know  oxygen,  azote  and  sulfur,  and  of 
these  oxygen  seems  the  most  active.  We  reason 
along  the  scheme 


Mixing  oxygen  and  salt  gas  at  ordinary  tempera- 
7 


98 


CHEMISTRY    SIMPLIFIED. 


ture  has  no  effect  as  seen  in  this  cylinder,  which 
holds  the  mixture ;  therefore  let  the  mixture,  one 
volume  of  each,  be  passed  through  the  glass  tube  T 
(Fig.  36)  and  let  asbestus  A  (mineral  wool)  partly 
fill  the  tube.  The  asbestus  being  brought  up  to 
redness,  the  gas  mixture  slowly  passes  through  it 
in  measure  as  the  cylinder  Cf  is  raised  and  the 
cylinder  C"  is  lowered.  While  C  fills  with  mercury 
the  pipette  P  fills  with  a  gas  of  pale-green  color. 

FIG.  36. 


This  gas  we  shall  hereafter  name  chlorine,  (Cl.)  from 
Greek  chloros  =  green.  For  consistency's  sake  the 
name  should  be  chlorium — as  hydrogenium,  ferrum, 
stannum,  potassium.  (The  great  chemist,  Berzelius, 
never  gave  up  his  belief  that  this  chlorine  was  a 
compound  and  not  an  element,  that  it  does  contain 
oxygen,  but  that  we  are  not  able  to  separate  the 
two.  The  demonstration  we  have  gone  through 
above  leaves  very  little  doubt  that  the  salt  gas  and 
hence  chlorine  do  not  contain  oxygen.) 

Chlorine,  physical    properties.      A   green   gas    of 


THE    LESSON    OF    COMMON    SALT.  99 

peculiar,  very  strong  odor ;  offensive  to  the  mucus 
membrane,  producing  ulceration  upon  the  latter 
down  into  the  bronchial  tubes  and  capillaries  of  the 
lungs,  painful  coughing ;  must  be  careful  not  to 
breathe  the  gas ;  if  necessity  compels  to  stay  in  a 
place  filled  partly  with  chlorine  must  keep  mouth 
and  nose  covered  with  a  wet  sponge.  The  gas  is 
very  heavy.  It  is  35.5  times  heavier  than  hydrogen, 
2.45  times  heavier  than  air,  and  2.216  times  heavier 
than  oxygen.  One  litre  of  the  gas  at  0°  C.  and 
760  mm.  mercury  pressure  weighs  3.178  grams. 
1  c.c.  equals  0.003178  grams,  roundly  3  milligrams. 
The  gas  dissolves  somewhat  in  water.  The  maxi- 
mum solubility  lies  at  9.5°  C.,  and  corresponds  to 
2.75  times  the  volume  of  the  water.  Hence  10  c.c. 
of  water  will  absorb  at  best  27.5  c.c.  of  the  gas. 
But  since  1  c.c.  of  gas  weighs  three  milligrams, 
the  27.5  c.c.  will  weigh  82.5  milligrams,  or  0.0825 
grams,  and  hence  in  weight  per  cent.  0.825.  It  is 
well  to  remember  that  the  most  concentrated  water 
solution  of  chlorine  does  not  contain  quite  one  per 
cent,  of  chlorine ;  at  30°  C.  only  1.75  volumes 
equals  0.525  weight  per  cent.  At  boiling  heat  the 
chlorine  is  completely  driven  from  its  solution. 

Chlorine  gas  condenses  into  a  mobile  yellow 
liquid  under  a  pressure  of  8.5  atmospheres  (127.5 
pounds  per  square  inch). 

Preparation  of  chlorine.  In  the  practical  prepara- 
tion of  chlorine  it  is  more  advantageous  to  supply 
the  oxygen  in  combined  form,  as  a  superoxyd,  an 
oxyd  which  contains  more  oxygen  than  it  can  hold 


100  CHEMISTRY    SIMPLIFIED. 

firmly.  Nature  furnishes  us  with  such  in  the  so- 
called  soft  manganese  ore  MnO2,  the  pyrolusite  of 
mineralogists.  The  salt-gas  acts  upon  this  oxyd 
even  at  ordinary  temperature ;  very  energetically  at 
about  60°  C.;  thus 

MnO2  +  4HC1  (salt-gas)  +  heat  ==  MnCl2  + 
2H20  +  2CL 

Only  one-half  of  the  chlorine  contained  in  the  salt- 
gas  appears  as  free  chlorine,  the  other  half  forming, 
with  the  metal  manganese,  a  pale,  rose-colored  salt 
— manganese  clilorid,  MnCl2. 

Neither  is  it  convenient  nor  economical  to  act 
with  the  salt-gas  upon  the  superoxyd.  A  solution 
of  the  gas  in  water  is  much  better  adapted  to  this 
purpose,  the  best  concentration  is  20  per  cent.  How 
to  make  such  a  solution  will  be  explained  in  the 
next  paragraph  below.  The  most  suitable  apparatus 
is  the  Koenig  generator,  represented  in  Fig.  37.  G 
is  the  generating  tube  drawn  out  at  lower  end  0, 
where  a  stout  rubber  tube  R  is  wired  onto  it.  The 
tube  R  has  at  its  other  end  a  bent  glass  spout  P, 
which  rests  upon  the  edge  of  the  waste  vessel  W. 
The  upper  end  of  G  is  somewhat  restricted,  and  a 
glass  stopper  S  is  ground  into  the  restriction.  This 
stopper  is  fused  to  the  funnel  tube  F,  the  latter 
carries  a  stop-cock  and  a  receiving  bowl  for  the  salt- 
gas  solution.  L  is  the  outlet  for  the  chlorine.  Jis 
a  wider  glass  tube,  fused  onto  6r,  so  as  to  form  a 
complete  jacket  around  the  latter.  The  tubulature 
E  serves  to  fill  this  jacket  either  in  part  or  entirely 


THE    LESSON    OF    COMMON    SALT. 
FIG.  37. 


101 


8 


$y  r//        YA  v-  ,    y        r^-- 

»» 


KOENlG'S   GENERATOR. 


102  CHEMISTRY    SIMPLIFIED. 

with  water  whilst  a  glass  tube  T encircles  the  jacket 
obliquely,  and  is  fused  into  the  jacket  at  both  ends. 
This  small  encircling  tube  is  full  of  water,  and,  be- 
ing heated  by  the  small  flame  from  a  glass  tube  or 
a  Bunsen  burner,  brings  up  a  circulation  and  raises 
the  temperature  in  /-to  any  desired  point.  Upon 
the  porcelain  false  bottom  I)  rests  the  manganese 
superoxyd  in  small  pieces,  about  pea-size.  The 
column  of  MnO2  should  not  be  over  3  inches  high. 
The  apparatus  is  held  by  the  brackets  B,  B,  B, 
against  the  wooden  stand  Q,  the  latter  being  sup- 
ported by  the  bottom  plate  N.  We  start  by  filling 
water  into  G  until  the  tube  R  is  full  and  the  water- 
level  in  the  spout  P  is  even  with  the  level  at  the 
false  bottom  D.  Then  we  heat  the  jacket  to  60°  C., 
and  thereupon  drop  the  salt-gas  solution  at  the  rate 
of  one  drop  a  second.  There  will  then  be  a  steady 
current  of  chlorine  gas  issuing  through,  whilst  an 
equally  constant  discharge  of  the  by-product,  i.  e., 
MnCl2  will  discharge  itself  at  P  into  the  waste 
vessel  Wj  provided  the  bowl  of  the  funnel  is  kept  re- 
plenished. If  a  stopping  be  desirable,  simply  turn 
the  stop-cock  in  F.  The  gas  will  not  be  quite  pure. 
It  will  be  mixed  with  some  liquid  particles  and  also 
with  some  salt-gas.  Hence  we  conduct  it  through 
a  wash  bottle  containing  some  water,  then  through 
another  such  containing  IPO. SO3;  in  the  latter  the 
aqueous  vapor  will  be  removed,  in  the  former  the 
other  admixtures.  Of  course,  whenever  dry  gas  is 
not  required,  the  second  wash  bottle  may  be  omitted. 
You  will  take  notice  that  the  rubber  tube  R  forms 


THE    LESSON    OF    COMMON    SALT. 


108 


a  trap  against  the  escape  of  the  gas  downward, 
whilst  the  narrow  funnel  tube  keeps  the  gas  from 
escaping  upwards.  But  it  stands  to  reason  that  if  a 
resistance  be  placed  at  L  of  greater  weight  than  the 
column  of  liquid  in  either  F  or  R,  then  the  gas 
escapes  through  them,  they  forming  the  natural 
safety  valve. 

A  generator   may   be   rigged    more  simply  and 

FIG.  38. 


cheaply.  A,  Fig.  38,  is  a  small  flask,  t  is  a  glass 
tube,  F  a  funnel  connected  with  t  by  a  short  rub- 
ber tube  and  clamp  C,  tf  tube  for  escaping  gas ; 
/•  a  i"  rubber  tube,  W  a  beaker  glass  in  which 
stands  a  large  test-tube  fitted  with  rubber  stopper 
/S',  and  partly  filled  either  with  water  or  with 
IPO. SO3  serving  as  wash  bottle.  The  manganese 
superoxyd  is  placed  in  A  at  M,  F  is  filled  with  salt- 


104  CHEMISTRY    SIMPLIFIED. 

gas  solution.  The  apparatus  is  ready  for  use.  In  a 
measure,  however,  as  MnCl2  accumulates  in  A,  the 
evolution  of  chlorine  becomes  slower,  a  steady 
stream  cannot  be  maintained  by  it,  except  for  a  very 
short  time.  I  worked  for  twenty-five  years  with 
such  an  apparatus,  until  I  made  the  more  perfect 
one  described  above. 

Chemical  properties  of  chlorine.  Chlorine  is  a 
most  powerful  agent  at  ordinary  temperature,  when 
oxygen  is  almost  inert.  It  attacks  all  the  metals, 
and  in  presence  of  water  dissolves  most  of  them  : 
Gold,  platinum,  tin,  copper,  iron,  zinc,  but  not  so 
lead,  silver,  mercury. 

Upon  oxyds,  it  acts  thus  : 

CuO     -f  2C1  +  heat  =  CuCP  +  0 
MnO2  +  2C1  +  heat  -  MnCl2  +  20 
Chlorine   acts   upon   all    coloring  matters  taken 
from  plants,   such  as  litmus,  indigo,  the  red  cab- 
bage,  and   many   others,  in  such  a  way  that  the 
color  vanishes,  bleaches. 

Upon  the  hydroxyds  of  potassium  and  calcium, 
chlorine  acts  as  follows : 

2CaO.H20  +  4C1  +  water  -  CaCl2  +  CaO.Cl'O  + 

2H20. 

The  milk  of  lime  becomes  dissolved  to  a  clear 
liquid.  If  the  dry  slaked  lime — flour  of  lime — be 
exposed  to  chlorine  the  same  action  takes  place,  but 
the  resulting  product  is  a  slightly  pasty  solid,  and 
is  called  bleaching  lime;  is  soluble  in  water,  and  is 
used  in  large  quantities  by  the  bleachers  and  dyers 


THE    LESSON    OF    COMMON    SALT.  105 

of  yarn  and  cloth.  The  compound  CaCl2  does  not 
bleach,  only  the  compound  CaO.CPO,  and  in  this 
only  the  oxyd  CPO  is  the  bleaching  factor. 

Upon  potassium  hydrate  the  action  is  parallel, 
thus : 

2KXO.H20  +  3C1  =  KC1  +  KXO.CPO  +  2H2O. 
You  pass  the  chlorine  gas  into  the  solution  so  long 
as  it  is  freely  absorbed.  The  result  is  a  bleaching 
solution.  But  if  we  boil  this  solution  for  some 
time,  it  begins  to  throw  out  scaly  crystals,  white  or 
colorless.  Let  these  crystals  be  separated  from  the 
liquid,  then  dried,  and  then  heated  in  a  closed 
glass  tube,  when  they  will  be  seen  to  melt  easily 
with  strong  evolution  of  gas.  The  gas  proves  to  be 
pure  oxygen.  (Explode  it  with  2  volumes  of  hydro- 
gen.) When  no  more  gas  is  given  out  the  residue 
contains  only  potassium  and  chlorine,  is  KC1.  The 
crystals  themselves  are  produced  from  the  boiling 
solution  by  the  following  reaction : 

6KXO  +  6C1  +  water  +  boiling  heat  =  4KC1  + 

KXO.CP05, 
and  when  the  crystals  are  decomposed  by  heat : 

KXO.CP05  +  heat  =  2KC1  +  O6. 
The  crystals  represent  a  compound  of  the  metallic 
oxyd  KX0  with  the  non-metallic  super  oxyd  C1205. 
The  latter  is  unstable,  overloaded,  hence  heat  breaks 
it  up  easily,  and  as  we  have  seen  above  that  chlorine 
drives  oxygen  from  the  oxyds,  the  final  result  must 
be  KC1  -f  6  oxygen.  The  crystals  shall  be  known  as 
potassium  chlorate.  It  is  a  very  valuable  compound 


106  CHEMISTRY    SIMPLIFIED. 

to  us,  because  we  can  obtain  by  it  at  any  time 
quantities  of  the  purest  oxygen. 

Manufacturing  process  for  potassium  chlorate.  The 
potassium  hydrate  is  relatively  costly,  the  cal- 
cium hydroxyd  very  cheap,  KC1  is  also  cheap  (a 
natural  mineral  sylvite).  On  passing  chlorine  gas 
into  water  in  which  have  been  slaked  3  equiva- 
lents of  calcium  oxyd  (burnt  lime)  at  boiling  heat 
until  the  liquid  has  become  clear,  we  have  a  solu- 
tion of  calcium  chlorate  (easily  soluble).  We  bring 
into  it  one  equivalent  of  KC1  and  potassium  chlorate 
falls  out  in  crystals  (because  it  is  not  readily  soluble 
in  water). 

Composition  of  salt  gas.  We  found  the  gas  com- 
posed of  hydrogen  and  chlorine.  Now  we  have  to  es- 
tablish their  ratio  in  the  compound.  If  we  pass  one 
volume  of  salt  gas  over  heated  zinc  repeatedly,  in  the 
apparatus  Fig.  36,  we  find  that  the  volume  of  the  gas 
becomes  reduced  to  one-half.  Chlorine  unites  with 
zinc,  becomes  solid  so  to  speak,  the  remainder  is  pure 
hydrogen.  Hence  we  deduce  :  Salt  gas  is  composed 
of  equal  volumes  of  hydrogen  and  chlorine  ex- 
pressed by  the  symbol  HC1.  If  we  fill  into  a  cylinder 
one  volume  of  hydrogen  and  one  volume  of  chlor- 
ine and  let  the  mixture  stand  in  the  diffused  day- 
light for  some  days,  the  volume  does  not  change, 
but  the  two  gases  shall  have  become  united  to  HC1. 
We  can  prove  this  by  introducing  a  few  c.c.  of 
water ;  the  gas  is  all  absorbed  by  the  water ; 
chlorine  would  have  only  been  slightly  absorbed, 
hydrogen  not  at  all.  Should  we  expose  the  mixture 


THE    LESSON    OF    COMMON    SALT.  107 

of  H  -|-  Cl  to  the  direct  sunlight,  the  union  would 
follow  at  once  with  explosive  energy.  It  is  import- 
ant to  note  that  the  volume  of  the  compound  is 
equal  to  the  sum  of  the  volumes  of  the  components ; 
neither  contraction  nor  expansion  taking  place.  This 
is  a  law  for  all  unions  of  gaseous  bodies  in  equal  volumes. 
The  name  for  the  compound  HC1  shall  be  hydrogen 
chlorid,  and  all  combinations  of  metals  with  chlor- 
ine shall  be  named  chlorids,  as  we  name  the  oxygen 
compounds  oxyds.  Some  chemists  speak  and  write 
chlorides,  oxides;  it  is  quite  immaterial  which  you 
use,  but  choosing  one  you  should  stick  to  ib;  the 
shorter  sound  would  seem  to  be  preferable. 

Properties  of  hydrogen  chlorid  :  A  colorless  gas  at 
ordinary  temperature,  powerfully  pungent  odor, 
exciting  the  mucous  membrane.  Near  the  freezing- 
point  of  water  at  +4.4°  C.  the  gas  becomes  a  liquid 
under  a  pressure  of  30.67  atmospheres  or  460  Ibs. 
per  square  inch.  At  a  temperature  of  — 73.3°  C. 
only  a  pressure  of  27  pounds  is  needed.  Liquid 
HC1  is  mobile  and  colorless,  heavier  than  water. 
No  practical  use  has  been  found  for  it.  The  specific 
gravity  of  the  hydrogen  chlorid  gas  is  1.255  (air  = 
1) ;  1  c.c.  of  it  weighs  0.00163  gram,  just  about  one- 
half  that  of  chlorine.  By  weight  the  gas  contains 
97.26  of  chlorine,  2.74  of  hydrogen.  1  volume  of 
water  can  absorb  500  volumes  of  HC1  gas  at  the 
freezing-point;  at  20°  C.  (common  temperature)  water 
absorbs  440  volumes  of  the  gas.  The  absorption  of 
the  gas  produces  heat.  This  would  lead  us  to 
think  that  there  must  be  a  chemical  affinity 


108  CHEMISTRY    SIMPLIFIED. 

between  HC1  and  IPO ;  that  there  must  be  hy- 
drates. In  fact  it  is  quite  probable  that  two  such 
exist.  For,  if  a  concentrated  solution  of  HC1  in 
water  be  heated  (a  thermometer  registering  the  tem- 
perature), it  will  give  out  for  some  time  only 
moist  HC1  gas.  The  temperature  having  risen  to 
100°  C.,  water  passes  over  with  HC1  and  a  very 
concentrated  solution  condenses  having  specific 
gravity  1.19.  As  the  temperature  rises  the  distil- 
late becomes  more  watery  until  the  temperature 
reaches  111°  C.,  at  which  it  remains  constant  whilst 
a  solution  distills  over  possessing  specific  gravity 
1.104.  This  solution  contains  21  per  cent.  HC1  and 
79  per  cent,  of  water,  nearly  the  hydrate  2HC1  -f- 
15H20.  A  second  hydrate  is  HC1  +  6H20. 

Hydrochloric  acid — Muriatic  acid — HC1  -f-  water. 
These  names  are  given  to  the  water  solution  of  HC1. 
We  speak  of  highly  concentrated  acid,  concentrated 
acid,  dilute  acid,  very  dilute  acid. 

Sp.  gr.     Per  cent.  HC1 

Highest  concentrated,       1.200  40.77 

Highly  concentrated,        1.1802         36.29 

Strong  acid,  1.151  30.58 

Medium,  1.072  14.68 

Dilute,  1.042  8.56 

Very  dilute,  1.006  1.12 

Problem :  Construct  with  these  data  a  curve  whose 

ordinates  shall  be  the  percentage  and  the  abscissae, 

the  specific  gravities. 

Preparation  and  manufacture.  Small  quantities 
are  made  by  distillation  in  glass  flasks  or  glass  re.- 


THE    LESSON    OF    COMMON    SALT. 


109 


torts.  On  a  commercial  or  manufacturing  scale, 
cast-iron  vessels  are  used,  either  cylinders,  or  else 
flat  pans  standing  within  a  brick  furnace.  Cast 
iron  is  not  attacked  by  concentrated  sulfuric  acid  nor 
by  HC1,  but  is  energetically  attacked  by  a  solution 
of  HC1  in  water.  Such  properties  render  the  iron 
vessels  fit.  Concentrated  sulfuric  acid  acts  violently 
upon  salt  even  at  ordinary  temperature  ;  the  mass 

FIG.  39. 


threatens  to  froth  over.  An  addition  of  water  gives 
relief.  Our  prescription  is :  For  every  ten  grams 
of  salt  take  9.6  c.c.  of  concentrated  IPO. SO3  and 
5.5  c.c.  of  water.  Mix  the  two  liquids  in  a  beaker- 
glass,  fill  from  it  the  basin  B  (Fig.  39)  of  the  funnel ; 
place  the  salt  in  the  flask  F ;  make  connection 
with  the  Wulf  bottle  W  by  tube  t  which  passes 


110  CHEMISTRY    SIMPLIFIED. 

under  the  level  of  the  wash  water.  The  tube  t'  also 
passes  under  the  surface  level  and  is  open  at  the 
top ;  t'  is  the  safety  valve  of  the  apparatus,  because 
air  will  pass  into  it  whenever  a  partial  vacuum  is 
brought  about ;  t"  leads  into  the  absorption  flask  A 
which  contains  as  much  water  by  weight  as  the  salt 
taken.  The  student  takes  50  grams  of  salt  and 
places  50  c.c.  of  water  in  the  absorption  bottle. 
The  stoppers  S,  8,  S  must  be  of  rubber.  The  flask 
F  must  hold  500  c.c.  All  the  acid  may  be  put  in 
at  once,  and  then  heat  applied  gently  at  first,  and 
regulated  to  keep  up  a  steady  evolution.  When  the 
gas  stops,  finally,  the  operation  is  terminated  and 
you  let  air  in  through  the  funnel  tube.  In  removing 
the  flame,  it  will  be  seen  that  the  liquid  in  F  solidi- 
fies, by  degrees,  as  it  cools  down.  Remelt  it  and 
pour  it  out  on  a  clean  stone  or  iron  surface.  Let  it 
be  named  "crude  salt  cake."  It  must,  evidently, 
be  the  vitriol  of  the  unknown  metal  M,  and  will  be 
taken  up  presently. 

Action  of  hydrochloric  acid.  The  water  solution  of 
HC1  is  nearly  as  powerful  an  agent  as  the  gas  itself, 
and  for  most  purposes  can  be  employed  in  its  stead. 
Because  the  metallic  chlorids  are  more  readily  solu- 
ble in  water  than  the  vitriols,  excepting  the  chlorids 
of  silver,  lead,  and  mercury;  therefore,  we  shall  use 
.it  in  preference  to  the  sulfuric  acid,  whenever  we 
desire  to  dissolve  bodies  which  are  not  soluble  in 
water.  As,  for  instance,  we  wish  to  generate  lime- 
gas.  The  calcium  vitriol  is  very  insoluble,  and  we 
have  heretofore  used  acetic  acid  for  the  decomposi- 


THE    LESSON    OF    COMMON    SALT.  Ill 

tion.  Instead  we  shall  use  hydrochloric  acid  here- 
after ;  the  calcium  chlorid  is  much  more  soluble 
than  the  vitriol,  in  fact,  it  will  dissolve  by  merely 
allowing  it  to  stand  uncovered  in  ordinary  air  which 
is  always  more  or  less  moist.  Hence,  we  can  em- 
ploy, to  advantage,  this  chlorid  in  place  of  concen- 
trated sulfuric  acid  for  the  drying  of  gases.  Being  a 
porous  solid,  the  calcium  chlorid  offers  more  surface 
to  the  gas  than  an  equal  volume  of  liquid  sulfuric 
acid. 

The  chemical  actions  may  be  represented  thus  :  If 
R  stands  for  a  metal,  whose  chlorid  is  soluble  in 
water  : 

R  -h  water  +  HC1  solution  =  RC1  solution  -f-  H  ; 
and  on  oxyds 

RO  +  water  +  2HC1  solution  —  RC12  solution  + 

H20; 

if,  however,  silver  vitriol  solution  be  brought  to- 
gether with  hydrochloric  acid,  a  white,  curdy  pre- 
cipitate falls  out  at  once,  AgCl, 

Ag2O.S03  +  water  +  2HC1  solution  =  2AgCl  + 

H2O.S03  solution 

because  the  silver  chlorid  is  insoluble  in  water. 
Thus  we  can  prove  the  presence  or  absence  of  silver 
in  any  unknown  solution  by  adding  to  it  a  drop  of 
hydrochloric  acid  ;  if  a  curdy  cloudiness  follows, 
then  silver  is  present. 

Pure  hydrochloric  acid  is  quite  colorless.  The 
yellow  color  of  the  commercial  muriatic  acid  is 
owing  to  some  iron  chlorid  coming  from  the  iron  ves- 


112 


CHEMISTRY    SIMPLIFIED. 


sels  and  iron  oxyd  in  the  crude  salt.  The  strength  of 
commercial  acid  is  mostly  indicated  in  degrees  on  the 
Beaume  hydrometer,  instead  of  by  the  specific  gravity. 
Such  an  instrument  (Fig.  40)  is  correct  if  it  sinks 
in  pure  water  at  17°  C.  to  the  zero  mark.  Zero  is 
therefore  equal  to  specific  gravity  1.000.  In  a  15 
per  cent,  solution  of  common  salt  (salt  =  15,  water 
=  85)  the  spindle  must  sink  to  the  mark  15;  the 
degrees  being  equal  divisions.  Very  concentrated 


FIG.  40. 


o  i:   \.ooo 


FIG.  41. 


hydrochloric  acid  is  said  to  be  22°  Be.  (specific 
gravity  1.176).  There  is,  of  course,  a  second  spindle 
for  liquids  lighter  than  water.  In  this  instrument 
(Fig.  41)  the  zero  point  is  near  the  bulb,  the  weight 
in  the  bulb,  being  so  chosen  that  the  spindle  sinks 
in  a  solution  of  10  per  cent,  salt  (salt  1,  water 
9)  to  the  zero  point,  whilst  in  pure  water  it  sinks  to 


THE    LESSOX    OP    COMMON    SALT.  113 

division  10 ;  the  same  unit  (found  by  dividing  the 
space  between  0  and  10  into  10  equal  parts)  is  then 
drawn  on  the  scale  upward  to  the  limit  of  the  spindle. 
Kerosene,  gasoline  and  other  coal-oil  products  are 
gauged  in  the  United  States  by  degrees  Be\  Alco- 
hol is  gauged  by  the  hydrometer  of  Tralles.  It  is  not 
sufficient  to  say  that  a  liquid  stands  at  so  many  de- 
grees Be.,  it  must  be  said  whether  reference  is  had 
to  a  liquid  lighter  or  heavier  than  water,  which  can 
be  done  by  the  signs  +,  — ,  or  by  letters  :  1.  w ; 
h.  w.  Thus  the  light  gasoline  for  gas-making  is 
— 87°  Ed,  and  the  concentrated  sulfuric  acid  is 
+  66°  Be'.  Hydrochloric  acid  can  be  shipped  only 
in  glass  vessels  ;  the  sulfuric  acid  can  be  transported 
in  iron  tanks.  The  glass  vessels — large,  spherical, 
holding  5  to  10  gallons,  and  being  packed  with 
straw  into  wooden  boxes — are  known  as  carboys. 
For  manufacture  on  a  large  scale  get  information 
in  Lunge's  Manufacture  of  Soda  Ash  (recent)  or  in 
Ure's  Dictionary  (old). 

Claude  salt  cake,  discovery  of  the  metal  sodium. 
Let  some  of  the  crude  cake,  obtained  by  action  of 
H2S04  on  salt,  be  heated  in  a  porcelain  crucible 
over  an  open  flame.  Dense  white  fumes  are  soon 
seen  to  arise.  The  fumes  are  now  diagnosed  by  us 
as  probably  being  sulfur  trioxyd,  oil  of  vitriol.  As 
the  vapors  escape,  the  melting-point  of  the  cake 
rises.  Finally,  when  no  further  fumes  come  off, 
the  stuff  appears  dry  at  a  red  heat.  At  yellow  heat 
it  melts  again,  and  remains  so  without  yielding  any 
more  fumes  or  gas.  Reason  for  the  fumes :  The 
8 


114  CHEMISTRY    SIMPLIFIED. 

crude  salt  cake  is  MSO.S03.H2O.S03,  a  so-called 
acid  vitriol,  quite  constant  at  low  heat,  but  break- 
ing up  at  high  heat  into  MSO.S03  +  JPO  +  SO3. 
The  final  remnant  is  MSO.S03  =salt  cake — refined. 
We  had  added  in  the  recipe  given  just  twice  as 
much  sulfuric  acid  as  is  needed,  and  did  this  know- 
ingly, for  otherwise  we  could  not  have  completely 
decomposed  the  salt  in  a  glass  flask  ;  the  stuff  would 
not  have  liquefied  ;  the  flask  probably  broken.  Salt 
cake  dissolves  in  cold  water  easily  ;  this  property 
distinguishes  it  from  the  potassium  vitriol  and  the 
calcium  vitriol.  In  order  to  isolate  the  metal  let 
us  make  use  of  our  experience  with  charcoal — car- 
bon. We  mix  the  powdered  salt  cake  with  powdered 
charcoal,  cover  the  crucible,  and  expose  it  in  a  char- 
coal or  gasoline  furnace  to  strong  red  heat.  We 
may  do  it  in  a  hard  glass  tube  first.  Result  is  a 
dark-colored  mass  ;  metallic  particles  are  not  visible, 
and  if  we  bring  it  together  with  water  there  is  no 
evolution  of  gas,  such  as  potassium  produced. 
However,  it  dissolves  in  water,  leaving  charcoal 
powder,  which  we  separate  by  filtration,  and  test, 
after  thorough  washing,  by  burning ;  as  it  quite 
disappears  (leaving  only  trace  of  ash),  we  are  correct 
in  calling  it  charcoal.  The  filtered  liquid  has  a 
brown  or  red-brown  color ;  it  gives  alkaline  reaction 
to  litmus ;  has  a  strong  taste.  With  hydrochloric 
acid,  gives  off  gas  smelling  of  rotten  eggs,  and  if 
this  gas  be  passed  through  a  glass  tube  heated  to 
redness  a  sublimate  of  sulfur  forms.  If  bright  cop- 
per or  silver  be  brought  together  with  the  liquid, 


THE    LESSON    OF    COMMON    SALT.  115 

the  metal  turns  black,  and  if  these  strips  of  black- 
ened metal  be  heated  in  an  open  tube  we  get  the 
smell  of  SO2.  If  boiled  with  finely-divided  copper 
oxyd,  the  liquid  becomes  decolorized  and  does  not 
any  more  blacken  the  metallic  copper,  whilst  it' 
gives  still  a  strong  alkaline  reaction.  From  all 
these  observed  facts  we  draw  the  following  deduc- 
tions : 

1.  The  action  of  charcoal  must  have  been,  sym- 
bolically, thus 

MSO.S03  +  nC  =  MSS  +  4CO  -f  n-4C  ; 
the  vitriol  was  converted  into  a  sulfid. 

2.  The  action   of  metallic  copper   and    metallic 
silver  was  probably 

MSS  +  nH20  +  Cu  =  CuS  (black)  +  MSO.H20 
(alkaline)  +  (n-1)  IPO. 

3.  The  action  of  copper  oxyd  was  probably 

MSS  +  CuO  +  nH20  =  CuS  +  MSO.H20  (alkaline) 

+  (n-l)H20. 

The  hydroxyd  of  the  unknown  metal  is  easily  solu- 
ble in  water,  and  being  strongly  basic — alkaline — 
it  must  be  akin  to  potassium.  We  evaporate  the 
liquid  from  (3)  to  a  white  solid,  which  afterwards 
fuses  and  then  goes  off  in  white  fumes,  just  like  potas- 
sium hydroxyd.  We  act  upon  this  material  with 
zinc,  and  by  evolution  of  hydrogen  prove  it  to  be 
hydroxyd.  Next  we  act  upon  it  with  the  electric 
current ;  gas  at  positive  pole ;  metallic  globules  and 
gas  at  negative  pole  ;  and  by  using  mercury  as  the 
negative  pole  we  obtain  a  solid  amalgam,  from 


1*16  CHEMISTRY    SIMPLIFIED. 

which  the  metal  M  may  be  separated  by  distillation 
in  a  current  of  hydrogen  gas.  If  we  act  upon  the 
hydroxyd  with  charcoal-loaded  iron  chips  at  a  yel- 
low heat,  the  metal  will  distil  over,  same  as  potas- 
sium, but  the  flame  issuing  from  the  retort  burns 
with  ^yellow  color  (distinction  from  potassium, purple 
flame).  In  the  neck  of  the  retort  we  find  a  black 
mass  which  acts  like  that  found  in  the  distillation 
of  potassium.  This  mass  is  mixed  with  the  con- 
densed metal. 

Properties  of  the  metal  sodium.  The  name  sodium. 
is  given  to  the  metal  by  English,  French,  and  Amer- 
ican chemists.  Germans  and  all  others  give  it  the 
name  natrium,  using  the  first  two  letters  as  the  sym- 
bol, Na,  which  stands  for  the  chemical  unit  of 
mass.  English,  Americans,  French  use  the  same 
s}^mbol,  hence  sodium,  Na.  Natrium  is  derived 
from  Greek  nitron ;  Egyptian  and  Hebrew  neter,  a 
name  given  by  those  people  to  the  crusts  forming 
around  the  desert  lakelets,  and  which  was  found  to 
have  similar  cleansing  properties  to  potash.  It  is 
now  known  as  soda  ash.  Whence  the  word  soda 
comes  is  not  known,  nor  what  it  means.  Perhaps 
from  the  Latin  soldere,  English  solder,  since  this 
material  may  have  been  confounded  with  borax, 
such  mixtures  being  useful  in  joining  metal  pieces 
by  heat.  (Author's  notion.) 

The  metal  sodium  is  soft  like  wax  at  ordinary 
temperature,  can  be  hammered  at  freezing-point, 
becomes  liquid  at  about  95°  C.  (melting-point 
is  higher  than  that  of  potassium  65°  C.).  In  color 


THE    LESSON    OF    COMMON    SALT.  117 

it  is  silver-white  like  potassium ;  the  fresh-cut  sur- 
face becomes  rapidly  dull  from  oxydation.  Sodium 
becomes  vapor  at  red  heat,  and  this  vapor  has  a 
purplish  color — potassium  green.  Specific  gravity 
at  10°  C.  is  0.974  (water  ==  1).  Coefficient  of  ex- 
pansion 0.000073,  larger  than  that  of  any  other 
metal  except  potassium  (0.000083).  It  conducts 
heat  and  electric  waves  well,  about  37  (silver  = 
100).  Its  specific  heat  or  heat  capacity  is  0.2934. 
Its  heat  of  fusion  is  0.73  Cal. 

Chemical  properties  of  'the  metal  sodium.  Thrown 
upon  water  it  sets  up  an  evolution  of  gas  and  melts 
into  a  globule  which  is  covered  by  a  gray  film. 
The  gas  does  not  ignite,  unless  the  water  be  heated 
to  about  60°  C.,  or  unless  the  water  be  thickened 
with  gum  arabic  or  glycerine.  We  deduce  from 
this  action  that  sodium  has  not  as  much  affinity 
or  attractive  tendency  for  oxygen,  as  potassium  ; 
hence  less  heat  is  generated.  If  the  globule  be  left 
on  the  water  until  the  gas  evolution  stops,  the 
globule  flattens  out  suddenly  and  an  explosion  en- 
sues. If  the  globule  be  taken  from  water  when  gas 
stops,  it  is  found  composed  wholly  of  oxyd.  (The 
explosion  is  explained  by  the  sudden  rise  of  steam 
when  the  oxyd  becomes  hydroxyd.) 

If  the  metal  be  heated  in  oxygen  gas,  or  in  a 
mixture  of  air  and  oxygen,  a  yellow  substance  re- 
sults which  is  the  superoxyd  of  sodium;  on  cooling  it 
turns  white.  It  dissolves  in  water  without  decom- 
position, and  can  be  melted  without  decomposition. 
If  heated  with  copper,  lead,  zinc  or  tin  the  sodium 


118  CHEMISTRY    SIMPLIFIED. 

superoxyd  changes  these  metals  into  oxyds.  With 
HC1  it  gives  NaCl  +  H20  +  0.  If  this  action  be 
done  in  water  solution,  oxygen  does  not  escape ;  the 
water  then  contains  sodium  chlorid,  NaCl,  and  hy- 
drogen superoxyd  (also  called  peroxyd),  H202  or 
HO  ;  we  assume  therefore  that  the  sodium  peroxyd 
must  have  a  similar  composition  to  the  hydrogen 
peroxyd,  namely,  Na202,  the  reaction  will  be 
Na202  +  2HC1  +  water  =  2NaCl  +  H202  +  water. 
This  solution  of  hydrogen  peroxyd  is  a  powerful 
oxydizing  agent  and  is  much  used  both  in  labor- 
atory work  and  on  a  large  scale  for  manufacturing 
purposes. 

If  the  superoxyd  has  the  composition  Na2  O2  then 
the  oxyd  must  be  Na2  0.  We  get  this  by  fusing 
together  the  hydroxyd  with  the  metal  in  proper 
proportion.  It  is  a  gray  substance,  and  of  no  spec- 
ial application.  It  attracts  moisture  from  the  air 
and  becomes  hydroxyd. 


CHAPTER  VII. 
THE  STORY  OF  SODA  ASH  AND  LEBLANC. 

WHEN  in  the  early  years  of  the  past  century  Na- 
poleon closed  all  the  harbors  of  Continental  Europe 
to  English  and  American  ships,  in  order  to  destroy 
the  commerce  of  England,  as  he  could  not  destroy 
its  navy,  there  arose  in  Continental  Europe  a  scar- 
city of  potash,  since  the  supply  had  nearly  all  come 
from  the  American  colonies.  To  ease  the  demand 
for  this  article,  as  well  as  to  spite  England,  Napo- 
leon offered  a  prize  of  100,000  francs,  20,000  dol- 
lars, for  the  discovery  of  a  substitute  for  potash. 
This  prize  was  won  and  awarded  to  the  French 
chemist  Leblanc,  who  proposed  a  process  by  which 
common  salt  can  be  turned  into  a  body  which  may 
be  substituted  for  potash  in  most  technical  applica- 
tions, a  process  which  held  its  own  for  80  years  and 
is  only  now  giving  way  slowly  to  better  meth- 
ods. (See  Solvay  process  at  end  of  chap.  XL)  All 
the  reactions  were  known  to  chemists  at  the  time 
but  one,  the  replacing  of  copper  oxyd  by  a  cheaper 
compound.  Leblanc  found  that  limestone,  or  oyster 
shells,  or  chalk  could  replace  the  copper  oxyd,  if 
the  action  takes  place  at  red  heat.  To  wit : 

Na2S  +  2CaO.CO2  +  red  heat  =  Na2O.C02  + 

CaO.CaS+  CO2. 

(119) 


120  CHEMISTRY    SIMPLIFIED. 

Na2O.C02  is  easily  soluble  in  water;  CaO.CaS  (cal- 
cium oxysulfid)  is  insoluble  in  water,  and  Na2O.C02 
is  the  practical  substitute  for  K2O.CO2  (potash). 
The  entire  run  from  salt  to  soda  ash  is  represented 
in  the  following  symbolic  scheme : 

(1)  2NaCl  (salt)  +  2H2O.S03  +  heat  =  2HC1  + 
Na2O.S03.H2S03. 

(2)  Na2O.S03.H2O.S03  +  heat  =  Na2O.S03  (salt 
cake)  +  SO3  +  H20. 

(3)  Na2O.S03  +  4C  +  2CaO.C02  (chalk)  +  yel- 
low heat  ==  Na8O.C09  +  CaO.CaS  +  CO2   -f  4CO 
(inflammable  gas). 

(4)  Na3O.CO8   +  CaO.CaS  +  water  +  heat  - 
CaO.CaS  (residue)  +  Na2O.C02  (solution). 

(5)  NaaO.COa  (solution)  -f  evaporation  =  Na2O. 
CO2,  soda  ash. 

The  soda  ash  produced  in  this  way  is  not  pure  : 
The  carbonate  predominates,  but  mixed  with  it  we 
find  Na2O.HaO,NasS  and  other  impurities.  It  can 
be  purified  ;  not  necessary  for  most  of  the  applica- 
tions, such  as  soap-making.  A  factory  in  which 
soda  ash  is  produced  goes  by  the  name  of  alkali 
works.  It  is  usually  divided  into  several  depart- 
ments, located  in  separate  buildings.  (a)  Acid 
works  where  the  sulfuric  acid  is  made,  (b)  Salt- 
cake  works,  (c)  Black  ash  smelter  and  extractor, 
(d)  White  ash  works,  (e)  Bleaching-lime  works, 
where  the  hydrochloric  acid  is  converted  into  chlor- 
ine and  the  latter  is  absorbed  by  the  dry  slaked 
lime. 


THE    LESSON    OF    SODA    ASK    AND    LEBLANC.       121 

SODA  ASH SODIUM  CARBONATE,  SAL  SODA, 

BAKING   SODA. 

When  the  liquid  resulting  from  action  (4)  (see 
above)  is  evaporated  to  dry  ness  and  then  fired  to 
red  heat,  the  product  bears  the  name  crude  white 
soda  ash.  If  the  same  liquid  is  however  only  evap- 
orated or  boiled  down  to  a  certain  point  and  is  then 
allowed  to  cool  slowly,  large  crystals  will  form. 
These  are  Na2O.C02  +  10H20  and  go  by  the  name 
sal  soda  (salt  of  soda).  The  impurities  remain  in 
the  mother  liquor.  If  they  be  exposed  on  wicker 
hurdles  in  an  exposed  space  into  which  lime  gas  is 
conducted  from  the  top  of  a  lime  kiln,  then  they 
will  pass  into  a  fine  granular  white  sandy  material 
whilst  water  runs  away  from  them.  The  white 
powder  goes  under  name  of  baking  soda,  bicarbonate 
of  soda.  The  action  is  thus  : 
Na2O.CO2  +  10H2O-hC02  (lime  gas)  =  Na2O.C02.- 

#20.<702  +  9H20. 

The  bicarbonate  is  slightly  soluble  in  cold  water,  and 
at  the  boiling  temperature  it  breaks  up  into  Na20.- 
CO2  +  CO2  -f  H20.  If  therefore  this  material  be 
mixed  with  flour  and  the  resulting  dough  is  put 
into  an  oven  we  will  just  get  that  same  decomposi- 
tion, the  escaping  lime  gas  causing  the  raising  of 
the  dough.  But  the  bread  must  taste  bitter  from 
the  sodium  carbonate  which  remains.  In  the  so- 
called  baking  powders,  the  baking  soda  forms  only 
one  ingredient,  the  other  being  an  acid  salt  which 
not  only  decomposes  the  carbonate  but  also  removes 
the  bitter  taste. 


122  CHEMISTRY    SIMPLIFIED. 

Caustic  soda  or  concentrated  lye,  of  the  manufac- 
turers is  made  by  decomposing  a  10  per  cent,  solu- 
tion of  soda  ash  with  one  equivalent  of  slaked  lime, 
the  same  process  we  considered  under  caustic  potash. 
The  resulting  solution  of  the  sodium  hydrate  is 
evaporated,  fused  and  cast  into  sheet-iron  drums,  or 
cans,  for  smaller  quantities,  or  into  one-pound  balls, 
which  latter  are  then  dipped  into  molten  rosin. 
The  film  of  rosin  keeps  the  material  from  attracting 
moisture  from  the  air  and  thus  liquefying.  The 
farmers'  wives  now  buy  these  lye  balls  for  their  soap- 
making  instead  of  bothering  with  the  wood  ashes. 
The  man  who  had  the  idea  of  the  rosin  film  made  a 
fortune  from  the  patent  rights. 

Certain  sea  plants  growing  in  the  tide  levels  of 
France  and  England,  called  kelp  in  Wales,  and 
varec  in  France  leave  an  ash  .which  is  largely  made 
up  of  sodium  carbonate,  the  plant's  energy  trans- 
forming the  salt  into  the  soda, 


CHAPTER  VIII. 

A  CHAPTER  ON  THEORIES;  ON  COMBINING 
WEIGHTS,   ATOMIC    WEIGHTS    AND    VALENCES. 

THE  existence  of  such  bodies  as  chlorids,  especially 
sodium  chlorid,  containing  no  oxygen,  and  yet  so 
much  alike  to  oxygen  salts,  leads  us  to  thinking. 
Let  us  compare  hydrogen  chlorid,  HC1  and  sulfuric 
acid,  IPO. SO3.  As  the  symbols  stand  written, 
two  do  not  seem  at  all  comparable.  But  supposing 
we  change  the  grouping  of  the  elements  in  the  sul- 
furic acid  thus  : 

H2O.S03—  H2.S04, 
then  at  first  glance  we  notice  the  resemblance, 

H.C1  — H2.S04, 
and  more  so  still  if  we  place  the  SO4  into  a  bracket, 

H(C1)  — H2(S04). 

We  have  no  knowledge  of  an  oxyd,  SO4  ;  we  only 
know  SO2,,  SO3,  S203,  S204  ;  yet  without  a  great 
wrench  we  can  imagine  that  the  very  moment  when 
the  two  oxyds,  H20  and  SO3,  are  brought  together, 
a  rearrangement  of  the  elementary  particles  comes 
ab.out  harmoniously,  quite  imperceptible  to  the  eye. 
As  soon  as  we  disturb  the  harmony  by  trying  to 
remove  the  hydrogen,  then  disarrangement,  a  break- 
up takes  place.  But  if  we  accept  the  reality  of 
(123) 


124  CHEMISTRY    SIMPLIFIED. 

this  improvable  state  of  things,  then  the  schism  in 
the  fundamental  chemical  phenomena  gives  way  to 
resolved  uniformity.  The  acids  become  then  combi- 
nations of  hydrogen  with  a  non-metallic  radical;  the 
radical  can  be  either  one  non-metallic  element  or  a 
group  of  such  elements.  In  hydrochloric  acid, 
chlorine  is  the  radical,  in  sulfuric  acid  the  group 
(SO4)  is  the  radical.  The  word  radical  is  the  adjec- 
tive of  the  Latin  noun  radix  =  root ;  from  the 
radical,  root,  arises  the  stem — the  sourness,  the 
acidity.  When  a  metal  acts  upon  an  acid,  hydro- 
gen escapes.  According  to  the  new  light  we  cir- 
cumscribe this  by  saying  the  metal  takes  the  place 
of  the  hydrogen  : 

H(C1)  +  K  =  K(C1)  +  H 

Why  does  it  do  so?  Because  potassium  has  a 
stronger  affinity  for  the  radical  chlorine  than  hy- 
drogen, and  this  stronger  affinity  is  made  percepti- 
ble by  the  greater  quantity  of  heat  which  is  set  free 
by  the  union  of  the  two.  If  Cal.  =  the  unit  of  heat, 
then 

H  +  Cl  =  HC1  +  nCal. 

K  +  Cl  =  KC1  +  n'Cal. 

n'>n. 

Metals  such  as  lead,  copper,  silver,  gold  do  not  act 
upon  the  dilute  acids;  they  are  not  dissolved  by 
them,  because  their  heat  of  formation  is  very  small 
and  requires  a  heat-addition  from  the  external  con- 
ditions. Thus  we  can  establish  a  series  of  the  metals 
in  which  potassium  will  occupy  the  one  flank  and 


A    CHAPTER    ON    THEORIES.  125 

gold  the  other  :  K.,  Na.,  Ca.,  Mn.,  Zn.,  Fe.,  Sn.}  Pb., 
Cu.,  H.,  Ag,  AU. 

If  we  designate  K  as  -f ,  then  Na  will  be  negative 
in  regard  to  K,  but  positive  in  regard  to  Ca,  and 
each  metal  in  the  same  way  positive  towards  its 
neighbor  on  the  right,  negative  towards  the  one  on 
the  left.  Equally  if  we  place  two  pieces  of  sheet 
metal  upon  one  another  with  a  moist  piece  of  felt 
between,  for  example,  zinc  and  copper,  an  electric 
tension  will  show  itself  between  them.  Galvani 
observed  this  120  years  ago,  and  his  name  is  at- 
tached to  this  electric  current  even  now — galvanic 
electricity  as  against  frictional  or  static  electricity. 
The  series  is  therefore  usually  alluded  to  as  the 
electro-chemical  series  of  metals. 

Of  the  non-metals,  oxygen  occupies  the  extreme 
flank,  with  chlorine  next,  as  sodium  stands  along- 
side of  potassium :  0.,  Cl.,  Br.,  S.,  N.,  C. 

Valence.  Glancing  at  the  symbols  H(C1),  H2(S04) 
we  cannot  help  but  being  struck  by  the  fact  that  in 
one  symbol  there  is  but  one  hydrogen,  whereas  there 
are  two  of  hydrogen  in  the  other.  We  cannot 
remove  one  of  these  hydrogens  without  destroying 
the  harmony,  without  breaking  up  the  body  com- 
pletely. To  give  expression  to  this  fact  we  are  led 
to  the  term  valence,  a  slight  difference  of  meaning 
from  equivalence.  We  say  the  elementary  group  (Cl) 
is  monovalent,  because  it  finds  its  satisfaction  with 
one  volume-unit  of  hydrogen,  monos  =  once ;  the 
compound  group  (SO4)  is  divalent,  dis  =  twice,  be- 
cause it  must  have  two  hydrogens  to  exist.  We 


126  CHEMISTRY    SIMPLIFIED. 

shall  find  later  on  elements  as  well  as  complex 
radicals  whose  valence  are  3,  4,  5,  6  designated 
respectively  as  tri-,  tetra-,  penta-,  hexavalent.  I  warn 
you  not  to  be  dazzled  by  these  full,  sonorous  words  ; 
they  are  but  a  short  cut  of  speech.  You  can  prove 
nothing  by  means  of  valence,  because  the  expression 
valence  only  states  a  fact,  yet  is  convenient  as  an 
expression. 

The  atomic  weights  of  elements,  molecular  weights  of 
compounds,  volume  weights.  We  find  that  one  vol- 
ume of  chlorine  unites  with  one  volume  of  hydro- 
gen ;  in  symbols  HC1.  Chlorine  gas  is  35.5  times 
heavier  than  hydrogen  gas  hence  the  symbol  stands 

HC1==  1  +  35.5  =  36.5 

Also  we  find  that  35.5  grams  of  chlorine  gas  com- 
bine with  23  grams  of  sodium  and  thus  produce 
35.5  +  23  =  58.5  grams  of  NaCl  (common  salt). 
Only  one  compound  between  Cl  and  Na  has  been 
observed  with  certainty  and  this  is  a  very  stable  one. 
We  assume  that  the  vapor  of  sodium,  if  it  could  be 
produced  and  weighed,  would  be  23  times  heavier 
than  hydrogen,  under  the  same  conditions  of  tem- 
perature and  pressure.  Though  the  metal  volati- 
lizes at  red  heat  yet  have  all  experimental  attempts 
thus  far  failed,  because  the  sodium  vapor  attacks  all 
the  vessels  which  are  available :  platinum,  gold, 
silver,  nickel,  porcelain  ;  hence  we  do  know  only  by 
inference  that  the  volume  of  the  mass  unit  weighs  23. 

Both  by  composition  and  decomposition  (synthesis 
and  analysis)  we  know  that  35.5  grams  of  chlorine 
gas  combine  with  39  grams  of  potassium  to  form 


A    CHAPTER    OX    THEORIES.  127 

35.5  +  39  grams  of  KC1.  That  39  is  the  weight  of 
one  volume  of  potassium  vapor  we  do  not  know  any 
better  than  in  the  case  of  sodium,  for  the  same  diffi- 
culties. The  symbol  KC1  or  XaCl  is  not  a  certainty 
in  other  words.  Its  strong  probability  follows  from 
the  following  consideration.  By  acting  upon  sul- 
furic  acid  H2(S04)  with  either  of  the  two  metals  we 
can  produce  well  crystallized  salts  or  vitriols  to  wit  : 


either  of  which  possesses  strong  acid  reaction,  and 


salts  which  are  neutral  towards  litmus  paper.  The 
former  salts  convert  into  the  latter  thus  : 

2XaH(SO)4  +  heat  =  XaNa(S04)  +  H2(S04)  vola- 
tilized 

2KH(S04)  +  heat  =  KK(S04)  +  H2(S04)  volatil- 

ized. 

Transposed  into  numbers  this  means  that  we  can 
combine  with  one  S  (32  parts)  either  23  or  46  of 
sodium,  either  39  or  78  of  potassium  ;  but  with  23 
and  39  only  when  in  each  instance  there  is  also  one 
hydrogen  present.  Hence  it  follows  that  23  of 
sodium,  39  of  potassium,  can  take  the  place  of  —  are 
equivalent  to  —  one  hydrogen  in  the  two  acids 

HC1,  H2S04. 
KC1,  K2S04. 
NaCl,  Na2S04. 


128  CHEMISTRY    SIMPLIFIED. 

Potassium,  sodium,  hydrogen,  on  these  given  terms 
are  monovalent  metals,  or  monads  (a  still  shorter 
expression),  It  is  self-evident  then  that  the  oxyd 
of  these  metals  must  be  Na20,  K20  if  the  oxyd  of 
hydrogen  is  H20.  The  hydroxyds  of  the  mefals 
sodium  and  potassium  become  Na2O.H20;  K20.- 
H20.  But  since  we  saw  in  the  vitriols  one  hydro- 
gen being  replaced  by  one  Na,  or  one  K,  the  same 
must  be  possible  in  water,  to  wit : 

H20  +  Na  =  NaHO  +  H  (escapes). 

Hence  it  follows  that  the  symbol  Na2O.H20  =  2 
(NaHO)  expresses  two  units  or  molecules  of  sodium 
hydroxyd,  that  NaHO  is  the  true  representation  of 
sodium  hydroxyd.  In  the  metallic  hydroxyd  we 
have,  therefore,  a  combination  in  which  the  metal 
is  united  to  the  group  (HO).  A  group  which  acts 
as  a  non-metallic  radical  of  the  value  (valence)  one. 
This  group  contains  the  metal  H  and  the  non-metal 
0,  whilst  the  negative  or  non-metallic  group  (SO4) 
contains  the  two  non-metals.  Perhaps  in  this 
hybrid  nature  of  the  group  (HO)  lies  part  of  the 
reason  for  the  action  of  the  hydroxyd  towards  lit- 
mus and  other  actions  totally  opposed  to  the  acids. 
The  relative  action,  then,  of  the  hydroxyds  and 
acids  is  this : 

Na(HO)  +  H(C1)  =  NaCl  +  H20, 
2Na(HO)  +  H2(S04)  =  Na2(S04)  +  2H2O. 

Two  attractions  exist  to  account  for  the  powerful 
action :  First  the  greater  attraction  of  the  metal  to 
the  non-metallic  radical  and  the  tendency  of  (HO) 


A    CHAPTER    ON    THEORIES.  129 

to  become  H20  by  taking  another  H.  Owing  to 
tbe  important  role  of  the  group  (HO)  the  name 
hydroxyl  (ule  =  matter)  is  given  to  it.  Hydrogen 
=  the  generator  of  water,  hydroxyl  =  the  matter 
from  which  water  is  made.  *  In  the  light  of  all  these 
considerations  and  speculative  deductions,  the  pre- 
vious definitions  of  base,  acid,  salt  shall  be  changed 
to  read  as  follows  : 

Base  =  Combination  of  metal  with  one  or  more 
hydroxyl  groups. 

Add  =  Combination  of  a  non-metallic  group  or 
radical  with  one  or  more  hydrogens. 

Salt  =  Combination  of  a  metal  with  a  non-metal- 
lic radical. 

The  definitions  of  acid  and  salt  are  identical. 
The  two  things  are  of  one  kind.  Sulfuric  acid  is 
hydrogen  vitriol. 

The  term  vitriol  has  been  abandoned  for  the  sake 
of  greater  uniformity  of  chemical  expressions.  Its 
place  is  taken  by  the  word  sulfate,  hence  the  fol- 
lowing : 

H2(S04)  =  Hydrogen  sulfate  =  sulfuric  acid. 
Na2(S04)  =  Sodium  sulfate. 
NaH(S04)  =  Sodium,  hydrogen  sulfate. 
K2(S04)  =  Potassium  sulfate. 
KH(S04)  =  Potassium,  hydrogen  sulfate. 
Ca(S04)  =  Calcium  sulfate. 
Fe(S04)  =  Ferro  sulfate  (iron  sulfate). 
Cu(S04)  =  Copper  sulfate. 
Pb(S04)  =  Lead  sulfate. 
Zn(S04)  =  Zinc  sulfate. 
9 


130  CHEMISTRY    SIMPLIFIED. 

You  should  accustom  yourself  to  use  the  expression: 
hydrogen  sulfate  in  place  of  sulfuric  acid,  though 
no  harm  is  done  by  the  latter.  Logical  consequen- 
tial speech  leads  to  logical  thought  and  work. 

Atomic  weight  of  calcium,  copper,  lead,  zinc.  By 
analysis  we  find  that  35.5  grams  of  chlorine  unite 
with  20  grams  of  calcium  to  a  stable  chlorid.  If  20 
were  the  representative  of  one  volume  of  calcium 
vapor  then  the  symbol  of  the  chlorid  would  be  CaCl, 
as  NaCl.  But  we  find  that  we  can  combine  the  cal- 
cium with  the  hydrogen  sulfate,  H2(S04),  only  in 
one  way,  not  in  two  ways  as  with  potassium  and 
sodium,  namely,  so  that  40  of  calcium  correspond 
to  one  (SO4)  or  one  S,  that  therefore  the  number 
40  must  stand  for  the  atomic  weight  of  calcium, 
that  one  calcium  is  equivalent  to  two  hydrogens  and 
therefore  the  symbol  of  the  chlorid  must  be  written 
CaCl2. 

not  -20Ca  +  35.5C1  =  CaCl, 
but  40Ca  +  2  X  35.5  =  CaCl2. 
Copper,  zinc,  lead,  also  form  only  one  kind  of  sul- 
fate, Cu(S04),  Zn(S04),  Pb(S04),  therefore,  we  say 
these  metals  are  divalent  like  calcium,  their  unit 
weight  stands  for  two  hydrogens,  and  in  each  case 
35.5  chlorine  combine  exactly  with  one-half  as  much 
metal  as  32  sulfur,  hence  their  chlorids  are  CuCl2, 
ZnCl2,  PbCl2.  Copper  makes  an  exception  in  so 
far  as  it  can  unite  with  chlorine  in  two  ways,  to  wit : 
35.5C1  +  31.5Cu  and  35.5C1  +  63Cu.  The  com- 
pound whose  ratio  of  Cl :  Cu  is  35.5  :  31.5  is  the  stable 
compound,  permanent  at  ordinary  heat  arid  even 


A    CHAPTER    ON    THEORIES.  131 

up  to  red  heat.  But  since  in  the  sulfate  32S  cor- 
respond to  63Cu,  therefore  we  take  the  number  63 
as  the  representation  of  one  divalent  volume  of  cop- 
per and  write 

63Cu  +  2  X  35.5C1  =  CuCP,  and 
2  X  63Cu  +  2  X  35.5C1  =  Cu2Cl2. 

In  the  first,  the  stable  compound,  cupric  chlorid, 
CuOl2,  the  metal  is  normal,  divalent.  In  the 
second,  the  unstable  compound,  cuprous  chlorid, 
Cu2Cl2,  the  metal  is  abnormal,  monovalent.  Sil- 
ver acts  like  potassium.  107. 6Ag  combine  with 
one  chlorine ;  but  2  X  107.6  combine  with  one  sulfur, 
32.  Hence  silver  is  monovalent,  107. 6 Ag  =  one  H. 
The  chlorid  is  AgCl,  the  sulfate  is  Ag2(S04). 

Gold  unites  with  chlorine  in  two  ways.  In  one 
compound,  which  is  a  whiter  powdery  substance,  we 
find  196Au  with  35.5C1,  in  the  other  65.33Au  with 
35.5C1.  The  first  compound  is  so  unstable  that  it 
falls  to  pieces  upon  the  addition  of  water.  In  the 
other  compound  the  chlorine  acts  upon  certain  sub- 
stances as  free  chlorine.  Besides,  the  specific  weight 
of  gold — 19.5 — is  so  high  that  necessarily  the  weight 
of  its  vapor  must  be  very  high  (though  we  cannot 
make  this  vapor).  We  take,  therefore,  196  to  repre- 
sent the  weight  of  one  volume,  and  write  the  sym- 
bols of  the  two  chlorids  : 
196Au  +  35.5C1  =  AuCl  =  aurous  chlorid, 
196Au  +  3  X  35.5C1  =  AuCl3  =  auric  chlorid. 

Auric  chlorid  is  a  deep  yellow  substance,  easily 
soluble  in  water,  and  fairly  stable.     In  it  gold  = 


132  CHEMISTRY    SIMPLIFIED. 

Au   has  the  valence  3.     In  aurous  chlorid  Au  has 
the  valence  1. 

Molecular  weight.  Two  or  more  simple  bodies 
united  into  a  chemical  union  form  a  molecule.  By 
some  it  is  contended  that  in  the  free  state  even  the 
simplest  bodies  —  the  elements  —  form  molecules,  that 
in  the  free  state  hydrogen  is  (H.H)  =  2,  chlorine 
(C1.C1)  =  71  ;  oxygen  (0.0)  ==  32,  and  H2(S04)  - 
98  of  course.  When  chlorine  acts  upon  hydrogen 
the  action  must,  according  to  this  view,  be  repre- 
sented by  : 


Nothing  is  changed,  in  reality,  by  adopting  this 
view,  or  by  rejecting  it.  If  we  speak  of  molecular 
weight  we  shall  invariably  mean  that  the  molecule 
is  composed  of  several  elements. 

Relation  between  atomic  weights  and  specific  heat  of 
the  elements.  By  heat  capacity  the  physicists  under- 
stand the  quantity  of  heat  energy  expressed  in 
calories  (heat  units),  which  is  necessary  to  raise  the 
temperature  of  a  mass  equal  to  one  gram  of  a  sub- 
stance by  one  degree  of  the  centigrade  thermometer. 
The  specific  heat  of  a  body  (solid  or  liquid)  means  its 
heat  capacity  referred  to  that  of  water  as  the  unit. 
The  specific  heat  of  gases  is  referred  to  that  of  air  or 
also  to  that  of  water  as  units.  The  variation  of 
values  thus  obtained  is  highly  astonishing.  In  gen- 
eral, the  heat  capacity  of  metals  is  very  low,  that 
is,  a  metal  shows  the  heat  very  quickly,  water  very 
slowly.  The  numbers  representing  the  specific 


A    CHAPTER    ON    THEORIES.  133 

heats  are  therefore  always  true  decimal  fractions. 
When  the  atomic  weights  of  the  metals  are  multiplied 
by  their  specific  heats  the  product  is  a  constant.  Reason 
therefore  demands  that  whenever  the  product  is  not 
equal  to  the  constant,  there  must  be  something 
wrong,  that  we  stand  before  a  riddle.  The  follow- 
ing numbers  show  this  relation,  which  is  also 
known  as  the  "  Law  of  Dulong  and  Petit :  " 

A.  W.  Spec.  Heat.  Product. 
Silver  Ag       108  X  0.0570  =  6.156 

Iron  Fe         56  X  0.1138  =  6.375 

Copper  Cu  63  X  0.0952  —  5.99 
Zinc  Zn  65  X  0.0955  =  6.207 

Calcium  Ca  40  X  0.167  -  6.68 
Sodium  Xa  23  X  0.2930  =  6.73 
Potassium  K  39  X  0.1655  =  6.45 

Lead  Pb        207  X  0.0314  ==  6.499 

Tin  Sn        118  X  0.0562  =  6.631 

These  numbers  do  not  show  exactly  the  same  pro- 
duct for  all  the  metals,  but  the  constant  appears  to 
be  about  6.5. 

Inversely  it  would  follow  that  the  specific  heat  of 
the  atomic  volume  is  the  same  for  all  the  metals  ;  the 
specific  heat  is  an  inverse  function  of  the  mass;  the 
greater  the  specific  gravity,  the  smaller  the  specific 
heat. 

REVIEW  OF  THE  ACTION  OF    CHLORINE  ON  THE  ALKA- 
LINE   HYDROXYDS. 

The  action  of  chlorine  upon  the  alkaline  hy- 
droxyds  is  so  important,  theoretically  and  practi- 


134  CHEMISTRY    SIMPLIFIED. 

cally,  that  we  must  now  transcribe  the  symbols  for 
those  reactions  according  to  the  notion  of  valence  : 

1.  2K(HO)  +  2C1  =  K(C10)  +  H20.  The  radical 
(CIO)  should  be  called  chloryl  like  hydroxyl,  but 
this  name  is  rarely  met  with.  It  cannot  be  iso- 
lated, it  has  no  real  existence,  it  is  unbalanced  ; 
C120  is  the  balanced  or  saturated  molecule. 

Cl2  0 — Dichloroxyd  is  at  ordinary  temperature  a 
reddish-yellow  gas  of  penetrating  odor.  Specific 
gravity  =  2.977.  1  cubic  centimeter  weighs  0.0039 
grams,  nearly  4  mgs.;  1  c.c.  of  chlorine  weighs 
0.00317;  1  c.c.  of  oxygen  weighs  0.00143.  2 
volumes  01  +  1  vol.  0  =  2  X  0.00317  +  0.00143  - 
0.00777.  If  the  latter  sum  be  divided  by  two  we 
get  0.00388  which  is  equivalent  to  the  experi- 
mental weight  0.0039.  Hence  it  follows  that  2C1  + 
10  =  3  vols.,  in  combining  to  Cl2  0  contract  one- 
third.  We  found  this  to  be  so  for  SO2  and  for  H20. 
We  may  deduce  the  general  law  that  two  volumes  of 
one  element  combining  with  one  volume  of  another  ele- 
ment always  produce  two  volumes  of  the  combination. 
Thus  is  explained  why  the  unit  weight  of  a  com- 
pound can  be  greater  than  the  sum  of  the  unit 
weight  of  its  composing  elements. 

C120  becomes  a  blood-red  liquid,  when  the  gas 
is  conducted  into  a  tube  which  stands  in  a  freezing 
mixture.  The  liquid  is  terribly  explosive.  A 
scratch  with  the  file  on  the  glass  tube  may  cause  an 
explosion;  the  C120  just  breaking  up  into  Cl2  +  0. 
This  is  an  interesting  fact.  For  in  spite  of  C120 
being  a  compound  like  water  IPO,  yet  whilst  the 


A    CHAPTER    ON    THEORIES.  135 

latter  is  strongly  cohering,  the  former  has  little 
coherence,  because  in  C120  we  have  two  non-metals, 
whilst  in  H20  we  have  metal  and  non-metal.  The 
compound  C120  is  made  by  acting  with  chlorine 
upon  the  oxyd  of  mercury,  thus :  HgO  +  4C1  = 
HgCl2  +  C120  (reddish-yellow  gas).  In  its  actions 
upon  metals  this  body  is  more  energetic  even  than 
chlorine  itself. 

When  chlorine  acts  upon  K(HO)  or  Na(HO)  or 
Ca(HO)2  at  boiling  heat  the  following  actions  occur  : 

6K(OH)  +  6C1  +  boiling  heat  =  K(C103)  +  5KC1  + 

3H20 
6Na(OH)  +  6C1  +  boiling  heat  =  Na(C103)  + 

5NaCl  +  3H2O 

6Ca(OH)2  +  12C1  +  boiling  heat  =  Ca(C103)2  + 
5CaCl2  +  6H20 

The  important  products  are  K(C103),  Na(C103), 
Ca(C103)2.  These  bodies  we  will  designate  chlo- 
rates. The  group  (CIO3)  is  a  monovalent  radical 
but  has  no  real  existence ;  neither  do  we  know  the 
corresponding  chloroxyd  C1205.  But  we  can  pre- 
pare the  hydrogen  chlorate,  H(C103).  It  forms  a 
thick,  syrupy  liquid  at  ordinary  temperature,  has 
strong  acid  taste,  no  odor.  Above  40°  C.  it  begins 
to  give  out  chlorine  and  oxygen. 

Potassium  chlorate,  is  as  above  stated,  the  most 
important  of  the  chlorates,  because  with  it  we  can 
generate  chlorine  gas  easily  in  immediate  contact 
with  the  bodies  to  be  acted  upon  : 

KC103  +  water  +  6HC1  =;  KC1  +  6CI  +  3H20, 


136  CHEMISTRY    SIMPLIFIED. 

Generation  of  pure  oxygen  gas  by  means  of  potassium 
chlorate. 

Equation  KC103  +  heat  =  KC1  +  30 
Converted  into  figures  this  means  :  Molecular  weight 
of  KC103  =  39  +  35.5  +  3  X  16  =  122.5  grams, 
give  48  grams  oxygen  gas.  One  cubic  centimeter 
of  oxygen  weighs  0.00143  grams,  hence  48  grams  = 
o.04osi43  c.c.  =  33636  c.c.  =  33.636  litres  =  0.033636 
cubic  meter. 

Problem.  Let  a  gas  holder  be  a  sheet-iron  cylin- 
der with  the  dimensions  :  Diameter  =  13.5  inches, 
height  =  27  inches.  How  many  grams  of  potas- 
sium chlorate  will  be  required  to  fill  this  holder 
with  oxygen?  1  inch  equals  2.5  centimeters  = 
0.025  m. 


CHAPTER  IX. 

BROMINE,  IODINE,  FLUORINE. 
BROMINE. 

IN  the  process  of  salt-making  from  natural  and 
artificial  salt  wells,  the  brine  (salt  solution)  is  evap- 
orated. At  a  certain  concentration  of  the  boiling 
liquid,  salt  crystals  fall  out  and  keep  on  precipitat- 
ing up  to  a  given  point.  The  crystals  are  steadily 
removed  by  means  of  a  sieve-ladle.  Finally  a 
heavy  solution  remains  from  which  no  crystals  of 
salt  fall.  This  solution  is  the  mother  liquor.  It 
contains  the  chlorids  of  calcium  and  magnesium, 
CaCl2  +  MgCl2  +  x,  x  being  the  combination  of  the 
new  element  bromine,  from  Greek  bromos  =  stench, 
with  magnesium.  If  the  mother  liquor  be  heated 
with  H2S04  and  MnO2  the  liquid  becomes  dark 
red-brown  and  heavy  red-brown  vapors  appear 
above  it.  The  vapors  condense  in  a  water-cooled 
receiver  to  a  deep  red-brown  liquid,  almost  black, 
and  emit  a  strong,  irritating,  suffocating  odor 
(indicated  in  name).  Specific  gravity  =  3.187  at 
0°  C.,  2.97  at  15°  C.  It  boils  at  63°  C.  and 
760  mm.  It  becomes  a  brown-red,  crystalline  solid 
at  — 24°  C.  The  symbol  for  bromine  is  Br.  Bromine 
gas  is  80  times  heavier  than  hydrogen.  In  most  of 
(137)  " 


138  CHEMISTRY    SIMPLIFIED. 

its  chemical  actions  it  is  similar  to  chlorine.  It  is 
soluble  in  water  ;  1  part  of  bromine  dissolves  in  33.3 
parts  of  water  at  15°  C.  The  solution  is  blood-red  in 
color,  and  gives  off  bromine  vapors.  It  is  soluble  in 
ether,  alcohol,  chloroform  and  carbon  disulfid.  If  a 
water  solution,  containing  little  bromine,  be  shaken 
with  carbon  disulfid,  the  bromine  will  leave  the 
water  and  pass  into  the  carbon  disulfid. 

1  vol.  Br.  +  1  vol.  H  +  heat  =  2  vols.  HBr. 
Hence  Br  is  monovalent  like  chlorine.     The  result- 
ing HBr,  hydrogen  bromid  is  a  colorless  pungent  gas 
like  HC1.  Liquefies  at  — 73 °C.  into  a  colorless  liquid, 
which  becomes  solid   when  the  liquid  HBr  is  al- 
lowed  to  evaporate  in  the  air.     One  c.c.   weighs 
0.003616  gr.     HBr  is  eagerly  absorbed  by  water, 
and  is  then  named  hydrobromic  acid.     The  highest 
concentration  is  82  per  cent.  HBr,  corresponding  to 
HBr  -f-  H20.     HBr  dissolves  metals  except  Ag,  Cu, 
Hg,    Pb,    because    the    resulting    bromids    AgBr, 
Cu2Br2,   Hg2Br2,   PbBr2,    are   not   soluble.     HBr 
combines  with  the  hydroxyds,  as  HC1  does  thus 
Na(HO)  +  HBr  =  NaBr  -f  H20, 
Ca(HO)2  -f  2HBr  -  CaBr2  +  2H20. 
Bromids  and  oxybromids  form  when  bromine  acts 
upon  the  alkaline  hydroxyds,  thus  : 

2Na(HO)+water+2Br  =  NaBr+Na(BrO)+H20, 
6Na(HO)  (concentrated) +6Br=5NaBr+NaBr03 
+  3H20, 

6K(HO)  (concentrated)+6Br  = 
3H20, 


BROMINE,  IODINE,  FLUORINE.  139 

Potassium  br ornate,  KBrO*,  is  even  more  insoluble 
than  KC103.  If  therefore  bromine  be  added  to  con- 
centrated solution  KOH  (1:3)  until  the  liquid  re- 
tains a  permanent  j-ellow  color,  KBrO4  will  fall  out 
as  a  crystalline,  colorless  powder;  KBr  remains  in 
solution.  KBrO3  can  be  made  pure  by  dissolving 
the  powder  in  boiling  water,  when  the  salt  will 
crystallize  on  cooling. 

The  most  important  salt  is  sodium  bromid,  NaBr. 
It  forms  a  part  of  bromo  seltzer  ;  is  much  prescribed 
by  physicians  against  headache.  Tons  of  it  are 
consumed  annually. 

Bromine  itself  and  bromine  water  are  valuable 
oxidizing  agents  in  the  hands  of  the  chemist.  Thus, 

SO2  +  2H20  +  2Br  =  H2(S04)  +  2HBr. 
Upon  heating  the  solution,  HBr  escapes  with  aque- 
ous vapor  and  leaves  hydrogen  sulphate.     There 
are  many  similar  actions,  with  which  we  shall  meet 
hereafter. 

IODINE. 

Before  the  discovery  of  bromine  a  French  chem- 
ist, Courtois,  had  found  a  strange  action  in  the 
mother  liquor  of  the  varec.  By  this  name  the 
peasants  of  the  Channel  Coast  in  northern  France 
designate  the  extract  from  the  ashes  of  the  sea 
weeds  which  are  thrown  ashore  by  the  storm.  These 
ashes  show  alkaline  reaction  like  the  ashes  of  land 
plants,  but  it  was  recognized  that  the  sodium  carbon- 
ate is  the  principal  component,  not  potassium  car- 
bonate, as  in  wood  ashes.  When  the  strained  lye 


140  CHEMISTRY    SIMPLIFIED. 

from  the  water  extraction  is  boiled  down,  potassium 
sulfate  falls  out  first  (being  least  soluble),  then  falls 
Na2S04  +  2H20,  then  NaCl,  then  Na2C03  -f 
3H20,  finally  leaving  a  mother  liquor  quite  strongly 
alkaline,  but  containing  still  NaCl,  together  with 
Na2C03  and  small  quantities  of  sulfur-compounds 
of  sodium.  To  this  mother  liquor  H2S04  +  water 
(1.7  sp.  g.),  pan  acid,  is  gradually  added  until  the 
solution  is  decidedly  acid.  CO2  escapes  and  hydro- 
gen sulfid,  while  a  scum  forms,  chiefly  consisting  of 
sulfur.  After  this  scurn  has  been  dipped  out  and 
the  solution  has  become  quite  clear,  it  is  transferred 
into  a  retort  (cast  iron  with  a  leaden  alembic  or 
cap),  manganese  dioxyd  is  added  and  heat  applied. 
Iodine  vapors  are  given  off  which  become  a  black 
crystallized  sublimate  in  the  receiver,  made  of  earth- 
enware. It  is,  however,  impure  with  salts  and 
water.  The  water  is  allowed  to  drain  off,  the  re- 
sidue redistilled  with  quicklime,  which  absorbs  the 
remaining  moisture.  The  nitre  works  of  Chili  fur- 
nish a  mother  liquor  from  which  large  quantities  of 
iodine  are  manufactured.  So  also  from  the  mother 
liquor  of  the  chemical  works  at  Stassfurt,  Germany. 
In  fact  iodine  or  rather  an  iodid  (either  Nal  or 
Mgl2)  is  contained  in  the  sea  water,  thence  it  gets 
into  the  algae  (sea  weed);  also  into  the  salt  beds  of 
the  earth ;  thence  into  all  salt  springs  and  wells. 
More  in  some  places  than  in  others.  The  sea  weed 
contains  up  to  0.6  p.  c.  of  iodine,  but  most  of  it  gets 
lost  in  the  drying  and  the  burning.  All  iodine  pro- 
ducers are  in  a  big  trust,  maintaining  high  prices. 
Probably  a  million  pounds  are  consumed  annually. 


BROMINE,  IODINE,  FLUORINE.  141 

Properties.  At  ordinary  temperature  a  grey-black 
solid,  always  crystals  or  crystal  fragments ;  metallic 
lustre;  emits  a  strong,  unpleasant  odor.  It  is  very 
soft.  Sp.  G.  4.958.  Melts  at  107°  0.;  boils  at 
180°  C.  The  vapor  of  iodine  is  of  a  beautiful  violet 
color.  The  name  iodine  from  iodos  —  similar  to 
violets,  was  given  for  this  color,  which  is  so  very 
characteristic  and  even  unique.  Water  does  not 
dissolve  iodine  freely.  One  gram  I  dissolves  at 
10-12°  C.  in  5524  grams  of  water.  This  solution 
is  known  as  iodine  water.  It  bleaches  the  same  as 
chlorine  water.  Much  more  soluble  in  alcohol. 
This  solution  is  known  as  tincture  of  iodine,  much 
used  by  physicians,  to  relieve  swellings  of  the  skin. 
Makes  a  dark -brown  stain  on  the  skin,  on  wool  or 
silk.  Iodine  dissolves  readily  in  a  water  solution 
of  potassium  iodid,  KI,  giving  a  yellow,  brown  or 
blood-red  liquid.  Soluble  in  ether,  in  carbon  di- 
sulfid.  If  a  trace  of  iodine  be  contained  in  much 
water,  or  salt  solutions,  a  few  drops  of  carbon  di- 
sulfid,  shaken  with  the  water,  will  absorb  all  the 
iodine  and  assume  a  rose  color  or  purple  color.  The 
vapor  of  iodine  is  127  times  as  heavy  as  an  equal 
volume  of  hydrogen  at  the  same  temperature. 
Hence  127  is  the  atomic  weight ;  the  symbol  is  I. 

Starch  and  iodine.  If  starch  be  boiled  to  thin 
paste,  and  the  paste  filtered,  making  a  clear  solu- 
tion, then  this  colorless  solution  will  become  in- 
tensely blue  if  a  small  quantity  of  iodine  solution  be 
added.  Starch  -f  iodine  equals  blue  body.  Thus 
we  can  recognize  starch  from  other  parts  of  a  plant 


J42  CHEMISTRY    SIMPLIFIED. 

or  seed  by  means  of  iodine,  and  detect  iodine  in 
solution  with  other  bodies. 

Chemical  properties.  Iodine  combines  with  the 
metals  directly  forming  iodids.  K  -f  I  —  KI  (with 
explosive  energy),  Na  +  I  =  Nal,  the  two  elements 
melt  together  without  explosive  display.  Hg  -f  21  -f 
heat  =  HgP  (producing  light)  a  scarlet-red  body. 
Hg  -f  I  ==  Hgl,  a  green-yellow  body.  These  iodids 
are  decomposed  by  bromine  ; 

KI  +  Br  ==  KBr  -f  I. 
Then  in  its  turn  KBr  +  Cl  give  KC1  +  Br. 
Chlorine,  bromine,  iodine  form  a  series  whose  chem- 
ical   affinity    is  inversely   as   their   atomic    weights 
which  are  35.5,  80,  127.     The  greater  the  mass,  the 
more  sluggish  the  activity. 

Iodine  does  not  readily  combine  with  hydrogen, 
as  chlorine  does.  It  requires  a  high  temperature. 
(6030  calories.) 

Hydroiodic  acid,  HI  -f-  water  is  best  prepared  by 
working  along  the  equation 

21  +  IPS  +  water  =  2HI  +  water  +  S. 
We  keep  the  finely  powdered  iodine  stirred  up  in 
water  whilst  the  gas  EPS  is  passed  into  the  water; 
the  color  of  the  solution  disappears.  HI  is  then 
dissolved  in  the  water,  the  sulfur  is  to  be  removed 
by  filtration.  The  liquid  is  strongly  acid,  smells 
pungent  like  HC1  and  acts  upon  metals  and 
hydroxyds  in  a  general  way  the  same  as  HC1.  A 
solution  of  Ag2S04  -f  HI  -f-  water  gives  a  yellow 
precipitate  of  Agl,  while  HC1  produces  a  white  pre- 
cipitate of  AgCL 


BROMINE,  IODINE,  FLUORINE.  143 

One  does  not  often  have  occasion  to  prepare  and 
use  HI. 

Oxyiodids,  iodates,  hydrogen  iodate,  HIO*.  By  the 
action  of  iodine  upon  KHO  we  obtain  KI  and 
K(I03).  6KHO  +  61  ==  5KI  +  K(IO*)  +  3H20. 
Potassium  iodate  is  slightly  soluble  in  water.  If 
K(C103)  be  dissolved  in  water,  to  the  liquid  finely 
powdered  iodine  added  and  the  solution  boiled, 
then  the  iodine  will  displace  the  chlorine. 
5K(C103)  +  61  +  3H20  +  heat  =  5K(I03)  + 

5HC1  +  HIO3. 

From  an  iodid  as  KI — chlorine  displaces  iodine ; 
but  from  a  chlorate  iodine  displaces  chlorine,  we 
say  :  Iodine  has  a  stronger  affinity  for  oxygen  than 
chlorine.  We  make  use  of  this  property  in  quanti- 
tative analysis. 

H(10*),  Hydrogen  iodate,  iodic  acid  is  formed  by 
acting  with  chlorine  gas  upon  water  in  which  finely 
ground  iodine  is  suspended— 

3H20  +  I  +  5C1  =  H(I03)  +  5HC1. 

If  a  dilute  solution  of  NalO3  be  heated  and  chlorine 
be  passed  through  until  no  further  precipitation  of 
salt  be  noticed,  then  the  precipitate  is  Na'2(I06)H2  or 
Na2O.H20(I04)  sodium  hydrogen  periodate,  and 
from  this  can  be  made  the  silver  salt  Ag(I04),  silver 
periodate. 

General  remarks.  The  most  important  compound 
of  iodine  is  KI,  potassium  iodid,  which  forms  white 
or  colorless  cubic  crystals,  like  KBr,  KC1;  the  three 
salts  are  isomorphous,  have  equal  form  and  can  re- 


144  CHEMISTRY    SIMPLIFIED. 

place  each  other  in  any  crystal.  We  can  have  a 
crystal,  any  particle  of  which  contains  K,  Cl,  Br,  I, 
even  the  very  smallest.  This  leads  us  to  the  con- 
clusion that  Cl  or  Br  do  not  in  reality  stand  for  one 
smallest  unit,  but  that  they  represent  a  vast  number 
each  of  smallest  units;  roughly,  the  circle  represents 
the  active  unit,  but  the  dots  mean  smallest  particles 
so  that  one  active  unit  may  contain  any  number  of 
isomorphous  particles  as  Cl,  Br,  I.  The  two 
spheres,  Fig.  42,  mean  the  molecule  K(C1,  Br,  I). 

FIG.  42. 


The  sphere  representing  potassium  contains  also  a 
multitude  of  smallest  particles,  which  in  their  turn 
may  be  a  mixture  of  any  number  of  isomorphous 
metals,  such  as  Na,  Ag.  That  is,  the  smallest  frag- 
ment of  a  microscopic  cube  might  contain  (K,  Na, 
Co,  Rb,  Tl),  (Cl,  Br,  I).  Minute  quantities  of  iodine 
are  found  in  the  blood  of  man  and  animals  as  well 
as  in  plants,  more  particularly  in  the  bones  of  the 
animal.  We  find  iodine  in  the  mineral  iodyrite, 
y  among  silver  ores  in  yellow  hexagonal  crystals. 


FLUORINE. 

The  mineral  fluorite,  fluorspar  from  German  fluss- 
spath,  occurs  widely  as  gangue  (German  gang  =  vein) 


BROMINE,  IODINE,  FLUORINE.  145 

or  vein-matter  with  silver-le'ad  ores,  sometimes  fill- 
ing considerable  fissure  veins  all  by  itself.  The 
German  miners  call  all  minerals  which  are  trans- 
parent or  translucent  and  possess  strong  cleavage, 
spath,  thus  calcite  is  kalkspath,  iron  carbonate  is 
eisenspath,  orthoclase  is  feldspath,  and  our  present 
mineral  was  named  flussspath  because  the  smelters 
noticed  that  it  melts  not  only  by  itself,  but  causes 
other  gangue  minerals  to  become  fluid,  in  other 
words,  to  act  as  a  flux  in  smelting.  Fluss  =  flux, 
whilst  fluere  is  Latin  for  to  flow. 

Fluorite  is  characterized  by  its  isometric  crystals, 
cubes,  octahedrons,  tetrahexahedrons,  hexoctahe- 
drons,  and  its  strong  cleavage  parallel  to  the  faces 
of  the  octohedron.  It  scratches  calcite,  is  therefore 
harder.  Mostly  colored  green,  purple,  pink,  blue, 
black,  yellow,  yet  these  colors  are  accidental,  do  not 
belong  to  the  substance  of  the  mineral  itself,  which 
is  colorless  or  white.  Shows  no  taste,  therefore  in- 
soluble in  water. 

Fluorite  melts  just  at  the  temperature  glass  melts  ; 
experiment  to  be  made  in  a  small  platinum  spoon 
or  crucible  ;  no  gas  will  be  given  out.  If,  however, 
we  put  a  piece  of  the  spar  upon  charcoal  and  direct 
a  strong  oxydyzing  flame  upon  it,  the  spar  will  melt 
at  first,  but  after  some  time  will  solidify.  Why? 
Because  the  conditions  are  different  from  those  in 
the  crucible.  The  flame  itself  is  not  a  mere  source 
of  heat,  but  a  mixture  of  gases  at  high  temperature. 
Among  the  gases  'are  aqueous  vapor  and  oxygen 
(from  the  air).  We  know  both  to  be  powerful 
10 


146  CHEMISTRY    SIMPLIFIED. 

agents  when  assisted  by  heat.  Indeed,  by  bringing 
the  nose  near  the  charcoal,  a  pungent  odor  becomes 
noticeable  ;  the  spar  decomposes  under  the  influence 
of  aqueous  vapor  and  heat  and  oxygen.  The  residue 
assumes  more  and  more  the  appearance  of  lime, 
glowing  incandescence.  By  acting  upon  the  finely  - 
powdered  spar  with  H2S04,  in  a  test-tube,  there 
appears  no  action  at  ordinary  temperature.  Upon 
applying  heat,  gas  bubbles  arise,  slowly  at  first, 
finally  in  large  number,  so  that  the  liquid  froths. 
A  gas  evidently  escapes.  To  the  nose  the  gas  is 
pungent,  acrid,  recalling  HC1,  but  more  repelling. 
Litmus  turns  red  at  once  in  the  gas. 

Investigation  of  the  gas.  Hypothesis  :  Having  an 
odor  like  HOI,  we  may  infer  that  the  gas  is  a  com- 
pound HnXm  or  perhaps  simply  HX  ;  and  proceed- 
ing a  little  further  with  the  assumption  that  X  is  a 
new  element,  let  X  at  once  be  represented  by  the 
letter  F  (first  of  fluor  spar) ;  hence  the  gas  may  be 
HnFm  or  perhaps  HF.  At  the  outset  in  the  in- 
vestigation, we  find  ourselves  confronted  with  a 
serious  difficulty.  Namely  we  find  the  test-tube, 
which  was  used  in  the  first  experiment,  strongly  cor- 
roded, after  it  is  washed  out  with  water :  The  gas 
evidently  decomposes  glass.  This  unwelcome  fact 
it  is  true  puts  a  sure  stamp  of  originality  upon  the 
new  element,  quite  unlike  any  other  thus  far  met 
with,  but  at  the  same  time  excludes  the  use  of  glass 
tubing  and  all  other  glassware.  On  porcelain  it 
acts  as  on  glass  ;  on  iron  and  zinc  it  acts  strongly, 
also  on  copper  and  silver.  Not  so  on  lead,  gold  and 


BROMINE,  IODINE,   FLUORINE. 


147 


platinum,  nor  on  wax,  paraffine  or  rubber.  The 
latter  materials  do  not  stand  heat.  We  are  thrown 
then  upon  the  three  metals,  of  which  lead  is  the 
cheapest.  The  gas  acts  somewhat  upon  the  lead 
surface,  but  the  product  of  the  action  being  nearly 
insoluble,  the  metal  answers  well  enough  for  all 
ordinary  purposes.  We  construct  a  distilling  ap- 
paratus of  which  Fig.  43  gives  a  sectional  represen- 

Fio.  43 


tation.  C  is  a  cup  of  sheet  lead  with  a  ring-shaped 
groove  G  at  the  rim.  The  cup  sits  in  an  iron  cup 
forming  a  sand  bath,  this  resting  on  the  tripod  T. 
Into  the  groove  G  fits  the  alembic  or  helmet  A, 
with  the  tube  neck  N.  After  filling  the  mixture  of 
fluorite  powder  and  H2S04  (so  much  acid  that  a 
thin  mush  forms)  at  M  into  the  cup  C',  the  alembic 
A  is  set  into  the  groove  G,  and  the  latter  filled  with 
plaster  of  paris  and  water.  The  plaster  sets  and 
forms  a  gas-tight  joint.  The  platinum  dish  D  is 
partly  filled  with  pure  water  and  so  placed  under 
JV  that  the  water  level  L  just  covers  the  mouth  of 


148  CHEMISTRY    SIMPLIFIED. 

N.  D  may  be  set  into  another  dish  and  surrounded 
with  snow  and  ice  or  salt.  When  the  lamp  is  put 
under  the  sand  bath,  the  air  is  first  driven  out,  then 
the  gas  appears  and  dissolves  in  the  cold  water.  If 
we  substitute  a  cylindrical  bottle  of  lead  or  platinum 
for  the  dish,  the  gas  itself  will  condense  into  a  liquid; 
specific  gravity  at  12°  C.  0.988,  nearly  equal  to 
water.  This  liquid  boils  at  19.5°  C.  It  fumes  in 
the  air ;  the  gas  combining  with  the  moisture  of  the 
air  gives  the  visible  fume.  Fumes  cause  violent 
coughing,  and  may  produce  death  if  taken  into  the 
lungs.  A  drop  of  the  liquid  will  produce  on  the 
skin  a  white  spot,  a  blister  forms,  bursts  and  a  pain- 
ful, slowly  healing  ulcer  forms.  Be  very  careful 
with  this  concentrated  liquid  ;  but  even  the  dilute 
water  solution  has  given  one  much  discomfort, 
when  some  of  it  got  under  the  finger  nails.  The 
perfectly  dry  gas  does  not  attack  glass ;  the  least 
moisture  causes  an  immediate  attack  ;  the  glass  be- 
comes opaque,  we  say  the  fluorspar  gas,  or  liquid, 
etches  glass;  German  aetzen,  French  mordre^  to  bite. 
To  etch  means  to  bite  out  something. 

Composition  of  the  gas.  When  the  gas  acts  upon 
Na,  K,  Zn,  Fe,  two  products  arise :  Hydrogen  -f- 
MenFm  (metallic  fluorid).  When  it  acts  upon  hy- 
droxyd  :  H20  +  MenFm  result. 

KHO  +  H»Fm  =  KnFm  +  H  20. 

That  the  gas  is  a  hydrogen  compound  of  the  radical 
F  there  can  be  no  doubt.  But  there  is  a  difference 
about  the  valence  of  F.  Because  there  is,  as  with 


BROMINE,  IODINE,  FLUORINE.  149 


the  molecule  H2S04  (see  above)  the  existence  of 
two  salts  to  wit  NaHF*  and  NaFx,  In  the  latter 
23  Na  (sodium)  are  combined  with  19  fluorine  (F), 
but  in  the  former  23  Na  are  combined  with  one  H 
and  38  F.  If  we  admit  the  proof  power  of  this  acid 
salt  (as  with  the  sulfate)  then  fluorine  (F)  is  divalent, 
the  sodium  fluorid  is  Xa2F,  the  atomic  weight  of 
F  =  38.  There  are,  on  the  other  hand,  quite 
weighty  reasons  why  we  should  assume  F  to  be 
monovalent.  Chiefly  the  closeness  between  its  ac- 
tion and  that  of  chlorine  is  convincing  to  the  large 
majority  of  chemists  to  declare  fluorine  a  monad 
and  its  atomic  weight  =  19. 

Sodium  fluorid  is  thus  made  NaF.  The  acid  salt 
is  XaH(F2).  The  solution  of  HF  in  water  is  hydro- 
fluoric acid.  The  acid  is  in  all  actions  closely  like 
HC1,  in  some  instances  however  fluorids  are  unlike 
chlorids.  When  a  water  solution  of  silver  sulfate 
is  added  to  HF  +  water,  no  precipitate  falls,  the 
AgF  being  easily  soluble  in  water,  whilst  AgCl  is 
insoluble  in  water.  On  the  other  hand,  calcium 
chlorid  CaCl2  is  very  soluble  in  water,  calcium 
fluorid  CaF2  is  insoluble  in  water. 

The  etching  process.  We  need  in  the  laboratory 
graduated  glass  vessels,  tubes  and  flasks  ;  or  we  want 
to  mark  and  number  the  vessels.  Hydrogen  fluorid, 
or  the  acid  salt  XaHF2  is  invaluable  for  this  pur- 
pose ;  they  can  be  bought  ready  for  use,  being  sold 
either  in  caoutchouc  or  ceresine  bottles  (ceresine  is 
mineral  wax).  First  cover  the  glass  with  a  thin 
film  of  paraffine  or  of  wax.  Melt  these  materials, 


150  CHEMISTRY    SIMPLIFIED. 

warm  the  glass  and  apply  the  liquid  material  with  a 
brush.  After  cooling  draw  the  mark  or  number  upon 
the  wax  or  paraffine  film  ;  then  scratch  away  the  film 
(with  a  steel  point)  all  the  lines  or  dots  which  are  to 
appear  in  the  etching.  After  this  two  ways  are 
open  :  (1)  to  expose  the  engraved  spot  to  the  slow 
vapors  of  HF  (this  gives  the  best  result);  or,  (2)  to 
apply  the  liquid  HF  by  means  of  a  camel's  hair 
brush  repeatedly,  according  to  the  desired  depth  of 
the  etching.  There  is  a  so-called  glass  ink  on  the 
market  which  appears  as  a  milky  white  liquid.  It 
is  a  solution  of  the  acid  salt  NaHF2  mixed  with 
plaster  of  paris. 

The  nature  of  fluorine.  When  HF  is  made  to  act 
upon  metallic  peroxyds  as  MnO2,  water  is  produced, 
MnF2  and  a  mixture  of  oxygen  with  fluorine. 
Many  statements  by  experimenters  are  on  record 
contradicting  each  other.  The  work  is  exceedingly 
difficult  arid  expensive.  No  pure  fluorine  has  as 
yet  been  obtained  by  the  above  method.  This 
much  seems  certain,  that  fluorine  possesses  a  color 
similar  to  that  of  chlorine,  i.  e.  yellowish-green,  that 
its  odor  is  similar  to  that  of  chlorine,  that  it  attacks 
all  substances  except  fluorspar,  especially  platinum 
and  glass,  and  bleaches  indigo.  This  state  of  affairs 
explains  why  we  are  uncertain  about  the  valence 
and  the  atomic  weight. 

The  metal  contained  in  fluorspar.  After  the  mix- 
ture of  spar  powder  with  H2S04  has  been  heated 
until  HF  no  longer  escapes,  but  the  thick  white 
fumes  of  H2S04,  that  means  when  complete  decom- 


BROMINE,  IODINE,  FLUORINE.  151 

position  has  taken  place,  we  find  the  residue  to  be  a 
semi-solid  which  is  soluble  in  a  large  quantity  of 
water.  From  the  solution  precipitate  characteristic 
monoclinic  crystals  of  calcium  vitriol  =  calcium 
sulfate  or  gypsum.  There  may  be  minute  quantities 
of  other  metals,  which  do  not  now  concern  us. 
Calcium  is  therefore  the  metal  of  fluorite,  it  is  cal- 
cium fluorid,  CaF2. 


CHAPTER  X. 

LECTUEE  ON  NITER  OR  SALTPETER. 

SALTPETER  or  niter  is  the  name  at  present  given 
to  a  peculiar  salt  of  immense  technical  or  industrial 
importance.  The  word  saltpeter  is  the  corruption 
of  Latin  =  sal  petrae  =  salt  of  the  rock  ;  niter  is  de- 
rived from  Hebrew-Egyptian  =  neter  thence  Greek 
=  natron-nitron,  thence  Latin  nitrum,  the  meaning 
of  which  has  been  explained  above  as  original  for 
natrium  =  sodium.  At  the  present  time  the  name 
applies  to  something  very  different  from  either  rock 
salt  or  soda.  It  applies  to  two  salts,  one  forming 
always  prismatic  crystals  of  the  orthorhombic  sys- 
tem, and  the  other  appearing  in  grains,  roughly  re- 
sembling common  salt.  On  closer  examination  the 
granular  crystals  are  seen  to  possess  rhomboid  faces 
not  rectangular  as  in  the  cube.  Geometrically  a 
cube  and  a  rhombohedron  are  riot  different  except 
as  to  the  position  of  the  faces  in  regard  to  a  system  of 
arbitrary  axes.  It  is  quite  possible  that  a  crystal- 
lographic  rhombohedron  has  rectangular  faces,  and 
a  crystallographic  cube  has  facial  angles  slightly 
deviating  from  90°.  The  action  of  a  crystal  towards 
the  polarized  light  alone  determines  the  system  of 
crystallization.  The  angle  of  the  pole  edges  is 
106°  30'  very  near  the  angle  of  the  cleavage  rhom- 
(152) 


LECTURE    ON    NITER    OR    SALTPETER.  153 

bohedron  of  calcite,  which  is  105°  30'.  At  all 
events  the  obliquity  of  the  angle  is  large  enough  to 
exclude  the  idea  of  the  cube. 

The  prismatic  niter  is  known  as  potash  niter,  the 
granular  rhombohedral  variety  is  known  as  Chili 
niter  or  soda  niter.  Both  varieties  are  easily  soluble 
in  water,  show  a  cooling  taste ;  nevertheless,  there 
is  a  marked  difference  in  the  solubility  of  the  two 
forms  of  niter.  100  grams  of  water  dissolve 

Soda  Niter.  Potash  Niter. 

at—     6°C.  68.8         at       0°  C.         13.3 

+  10°  C.  84.3  +18°  C.         29.0 

+  20°  C.  89.5  +45°  C.         74.6 

-1-100°  C.         168.2  +97°  C.       236.0 

Between  0°  and  100°  C.  the  ratio  of  solubility  is 
for  soda  niter  ±f£-  =  f  ;  for  potash  niter  -2r3/  =  \8-. 
Both  niters  melt  easily.  Potash  niter,  when  held 
in  the  flame,  gives  a  purple  color,  soda  niter  a 
yellow  color  to  it.  About  the  localities  and  condi- 
tions where  and  under  which  the  niters  are  found, 
we  will  speak  at  the  end  of  this  investigation,  as  you 
will  be  better  able  to  understand  several  of  the 
intricate  questions  which  arise  in  connection  with 
these  bodies. 

Investigation  of  the  soda' niter.  Let  first  a  crystal 
fragment  be  heated  in  a  closed  tube.  When  the 
heat  rises  to  redness,  we  notice  gas  bubbles.  On 
trying  the  gas  we  find  it  to  act  like  oxygen,  being 
without  odor,  and  being  able  to  fan  a  dark  red 
glowing  taper  into  bright  incandescence.  Now  let 


154  CHEMISTRY    SIMPLIFIED. 

us  drop  a  small  piece  of  feathered  tin  into  the  molten 
niter.  Notice  the  intense  action,  emission  of  light 
and  conversion  of  the  tin  into  white  oxyd.  Repeat 
these  actions  with  sulfur,  with  antimony,  with  char- 
coal ;  in  all  these  cases  there  is  displayed  the  phe- 
nomenon of  burning,  of  combustion.  Similar  action 
is  displayed  by  melting  potassium  chlorate.  We 
may  then  rightly  infer  that  niter  is  a  salt  similar  to 
K(C103),  or  Na(C103),  but  that  the  salts  are  not 
identical  follows  from  several  reasons :  (1)  unlike 
form  of  crystals,  (2)  great  difference  in  solubility, 
(3)  that  the  chlorates  part  with  their  oxygen  easily 
at  low  temperature,  whilst  niter  only  parts  with  it 
at  red  heat,  (4)  that  a  brown  gas  arises  from  the 
niter  when  it  burns  up  a  piece  of  metal,  of  sulfur  or 
wood,  (5)  that  this  brown  gas  is  suffocating.  The 
unavoidable  conclusion  points  to  the  existence  in 
niter  besides  sodium  and  oxygen,  of  another  un- 
known element.  Let  this  element  be  designated  by 
N  the  first  letter  of  niter,  and  let  it  be  pronounced 
nitrogen  =  generator  of  niter ;  then  soda  niter  will 
most  probably  be  NanNmOp,  and  of  potash  niter, 
KnNmO.  What  is  the  nature  of  N  ?  What  is  the 
ratio  of  its  combination,  what  are  the  numerical 
values  of  n,  m,  p? 

(1)  What  is  the  nature  of  N —  of  nitrogen?  Let  us 
return  first  to  that  experiment  in  which  the  niter 
was  heated  by  itself,  yielding  oxygen.  On  acting 
upon  it  with  water  we  will  get  a  solution  which 
shows  strong  alkaline  reaction  ;  the  niter  itself  has 
a  neutral  reaction — neither  acid  nor  alkaline.  This 


LECTURE  ON  NITER  OR  SALTPETER.     155 

may  mean  that  Xa*0  has  formed,  and  likewise  that 
a  compound  has  formed  with  less  oxygen  than  the 
original  niter,  i.  e.,  NanNmOp^.  Incidentally  we 
noticed  a  strong  corrosion  of  the  glass  tube  at  the 
places  where  the  niter  had  been  longest  exposed  to 
the  flame,  which  suggests  Na2O,  because  we  know 
from  handling  NaOH  and  Xa*C03  in  the  glass 
tubes  that  these  bodies  attack  the  glass  at  high  heat. 
In  the  water  solution  would  either  be  Na(HO)  -+- 
XauXmOp"q  or  only  one  of  the  two.  Addition  of 
dilute  H2(S04)  will  neutralize  Xa(HO). 

2XaHO  +  H2(S04)= Na2(S04)  +  H20=neutral ; 
a  further  addition  of  H2(S04)  will  cause  the  evolu- 
tion of  a  gas  of  peculiar  odor,  rather  aromatic.  The 
gas  may  be  H2NmOp"q  or  not ;  at  any  rate  it  is  a 
peculiar  body.  Now  let  us  act  with  concentrated 
H2(S04)  upon  the  original  niter.  At  ordinary  tem- 
perature there  is  but  little  if  any  action,  except  that 
the  niter  seems  to  dissolve,  at  least  partly,  and  but 
a  faint  odor  is  noticed.  As  heat  is  applied,  efferves- 
cence ensues.  A  sour,  pungent  gas  appears,  which 
condenses  in  a  sufficiently  cold  receiver  into  a  liquid, 
or  else  is  energetically  absorbed  in  water.  In  the 
residue  we  have  sodium  hydrogen  sulfate  +  hydro- 
gen sulfate.  We  pour  it  into  a  porcelain  dish,  and 
may  convert  it  into  salt  cake  by  means  of  heat ; 
prove  it  to  be  Xa2S04  by  means  of  its  easy  solu- 
bility in  water  and  its  resistance  to  crystallization. 
Only  low  temperature  will  induce  crystals.  The 
liquid  distillate  we  will  name  spirits  of  niter.  We 
study  its  action  upon  the  metals,  upon  paper,  wood, 


156  CHEMISTRY    SIMPLIFIED. 

the  skin,  wool,  in  fact  upon  all  bodies  known  to  us 
and  handy  to  procure.  For  remember  always  that 
chemistry  means  try  anything  upon  everthing  else. 
All  the  actions  will  be  remarkable. 

Lead  (Pb)  +  sp.  niter  -f  heat=white  salt  +  brown 
fumes. 

Copper  (Cu)  +  sp.  niter=blue  salt  -f-  brown  fumes. 

Silver  (Ag)+sp.  niter=white  salt-f  brown  fumes. 

Filter  paper  -h  sp.  niter  -j-  heat=solution+brown 
fumes. 

Gold  (Au)  -f-  sp.  niter  -f  heat  =  no  action. 

Platinum  (Pt)  -f  sp.  niter  4-  heat  =  no  action. 

Tin  (Sn)  +  sp.  niter=white  oxyd  +  brown  fumes. 

Hydrochloric  acid  (HC1)  -j-  sp.  niter  +  heat  = 
brown  liquid  -f-  brown  fumes. 

HC1  +  sp.  niter-j-gold  -j-  warm  =  yellow  solution, 
AuCl3  -f  brown  fumes. 

HC1  -f  sp.  niter  -f  platinum  =  yellow-brown  solu- 
tion -|-  brown  fumes. 

The  spirits  of  niter  proves  itself  thus  one  of  the 
most  powerful  agents.  The  Arab  chemist  Geber 
was  the  first  to  mention  this  body.  The  Latin 
translation  of  his  works  speaks  of  it  as  aqua  fortis 
(the  strong  water)  or  aqua  dissolutiva  (the  dissolving 
water)  because  it  dissolved  both  silver  and  lead. 
But  the  combination  of  the  spirits  of  salt  (HC1)  with 
the  spirits  of  niter  went,  and  still  goes,  by  the  name 
aqua  regia  (the  kingly  water),  because  it  dissolves 
gold,  the  very  king  of  the  metals. 


LECTURE    ON    NITER    OR    SALTPETER. 


157 


On  the  other  hand,  if  we  dilute  first  the  spirits  of 
niter  with  water,  very  considerably,  then  we  get 
hydrogen  when  acting  upon  either  iron  or  zinc,  but 
not  with  lead,  copper  or  any  other  metal ;  with  all 
of  these  it  is  either  brown  fumes  or  nothing.  Re- 
member the  similarity  with  the  actions  of  oil  of 
vitriol  or  of  the  concentrated  sulfuric  acid.  Con- 
centrated acid  on  the  metals  gave  vitriols  and  SO2  ; 
diluted  acid  on  iron  or  zinc  gave  vitriols  and  H. 
Just  as  SO2  was  demonstrated  as  an  oxyd  with  less 
oxygen  than  the  sulfur  oxyd  which  constitutes  the 
sulfuric  acid,  so  it  follows  logically  that  in  the  action 
of  the  strong  spirits  of  niter,  the  brown  fumes  must 

FIG.  44. 


constitute  a  lower  oxyd  of  the  nitrogen,  the  element 
whose  properties  we  are  after.  But  if  thus  the 
metals  can  take  away  oxygen  from  the  nitrogen,  we 
argue,  at  a  temperature  below  even  the  boiling-point 
of  water,  will  it  not  seem  probable  that  at  a  still 
higher  heat  more  will  be  taken,  or  perhaps  even 
all? 

We  set  up  an  apparatus  as  shown  in  Fig.  44.     F 
is   a   small    flask    with    twice    perforated    stopper. 


158  CHEMISTRY    SIMPLIFIED. 

Through  the  latter  pass  the  stem  of  a  funnel  2  and 
the  delivery  tube  3.  In  F  we  place  finely  divided 
copper,  K (gauze,  granules,  chips).  The  funnels  hold 
the  diluted  spirits  of  niter.  3  connects  with  U-tube 
4-.  The  latter  is  partly  filled  with  concentrated 
H2S04  forming  a  trap  to  dry  and  control  the  escap- 
ing gas.  5  is  a  tube  filled  with  quick -lime  (CaO) 
between  two  cotton  plugs.  In  the  charcoal  furnaces 
F',  F',  lie  the  hard  glass  tubes  T,  T',  each  charged 
with  rolls  of  copper  wire-gauze.  By  means  of  rub- 
ber tube  6j  T'  connects  with  the  bell  jar  B,  which  is 
filled  with  boiled  water  (in  order  to  expel  any  ab- 
sorbed air).  Before  connecting  F  with  tube  7  we 
heat  up  the  furnaces  and  pass  hydrogen  through 
T,  T',  in  order  to  have  perfect  metallic  surface  on 
the  copper.  The  tube  5  will  act  as  dryer  and  will 
also  retain  any  gas  of  an  acid  nature.  While  the 
action  of  hydrogen  was  going  on  in  T,  T',  we  have 
utilized  time  by  starting  the  action  in  F  so  that  all 
the  air  is  driven  out  by  the  gas.  We  regulate  the 
flow  of  liquid  from  the  funnel,  so  that,  if  possible, 
the  sulfuric  acid  trap  in  4-  will  indicate  the  passing 
of  a  slow  current  of  gas.  The  slower  and  steadier 
(not  in  gulps)  the  current,  the  better  will  be  the 
chances  of  a  perfect  deoxydizing  action.  Before 
connecting  T  with  tube  5  by  a  rubber  tube  7  we  re- 
move most  of  the  charcoal  from  F,  I ',  let  the  tubes 
T,  T'  come  down  below  red  heat,  for  the  unknown 
niter  gas,  being  an  oxyd  might  produce  with  the 
hydrogen  an  explosive  mixture.  When  we  connect 
7  with  T'  we  wait  a  sufficient  time  to  let  the  hydro- 


LECTURE    OX    NITER    OR    SALTPETER.  159 

gen  be  displaced  by  the  niter  gas,  then  we  replace 
the  charcoal,  get  a  good  heat,  cherry  red,  being 
always  careful  to  protect  the  rubber  stoppers  in  T 
and  T'  by  guarding  shields  and  dropping  water, 
and  again  after  some  minutes'  wait,  we  connect  the 
rubber  tube  6  with  the  bell  jar  B.  In  the  position 
as  shown  in  the  figure  there  will  be  suction  through 
the  chain  of  apparatus  as  soon  as  the  stopper  8  is 
opened,  owing  to  the  difference  of  level,  k,  between 
the  water  inside  and  outside  the  bell.  Therefore  all 
stoppers  and  connections  must  have  been  made  air- 
tight, otherwise  air  will  be  sucked  into  the  appara- 
tus :  The  true  nature  of  nitrogen  will  be  masked.  We 
maintain  the  action  until  B  is  filled  with  gas,  or 
until  several  holders  shall  have  been  filled. 

Properties  of  nitrogen.  After  having  been  pro- 
duced, as  just  stated,  the  gas  possesses  the  characters 
of  an  element.  With  present  means,  it  cannot  be 
further  split.  A  gas  devoid  of  color,  odor,  taste. 
Specific  gravity  14  (H  =  1) ;  0.9674  (Air  — 1). 
This  specific  gravity  is  so  nearly  the  same  as  that 
of  the  azote,  the  nonrespirable  part  of  the  air,  this 
being  0.9713,  that  we  are  justified  in  declaring  azote 
=  nitrogen,  because  the  nitrogen  also  is  nonrespir- 
able, it  causing  death  by  suffocation.  The  gas  is  but 
very  slightly  soluble  in  water,  it  is  not  absorbed  by 
the  alkalies.  It  is  very  indifferent  towards  all 
agents,  and  yet  it  is  evident  that  under  certain  con- 
ditions it  may  be  made  to  unite  with  oxygen  in 
several  ratios,  and  also  with  hydrogen  giving  rise  to 
a  most  interesting  body.  Nitrogen  we  shall  find  in 


160  CHEMISTRY    SIMPLIFIED. 

all  animal  and  plant  bodies,  constituting  the  essen- 
tial constituent  of  protoplasm,  the  body  which  is  at 
present  taken  to  be  the  basis,  the  substratum  of  all 
life.  It  is  important  to  note  that  nitrogen  has  no 
property  by  which  we  can  at  once  identify  it,  ex- 
cept the  specific  gravity  ;  all  other  properties  are 
mere  negations  of  the  properties  possessed  by  other 
gases. 

Properties  of  the  spirits  of  niter  and  its  quantitative 
composition.  Acting  with  the  spirits  of  niter  upon  a 
metallic  oxyd  (MeO)  we  get  water  +  niter.  The 
most  suitable  metallic  oxyd  for  our  present  purpose 
is  lead  oxyd  PbO  which  has  the  pale  yellow  color ; 
the  red  oxyd  is  not  equally  suitable.  Acting  upon 
Na(OH)  or  K(OH)  we  restore  the  original  niter, 
either  soda  niter,  or  potash  niter  and  water.  There 
is  only  one  salt  formed,  no  acid  salt  having  been 
obtainable.  Hence  the  radical  contained  in  the 
spirits  is  there  combined  with  one  H,  the  radical  is 
a  monad,  and  will,  therefore,  be  represented  by  the 
symbol 

H(NmO) 

Hence,  also,  if  we  act  with  the  spirits  upon  lead 
oxyd,  the  reaction  must  be 

PbO  +  2H(NmO)  =  Pb(NmO)2  +  H20. 

Like  the  soda  and  potash  niter,  the  lead  niter  con- 
tains no  water,  except  a  trifle  with  the  mother 
liquor.  The  white  or  colorless  crystals  of  this  lead 
niter  are  rhombohedral,  hence  isomorphous  with 
the  soda  niter.  It  is  best,  because  most  rapid,  to 


LECTURE  ON  NITER  OR  SALTPETER. 


161 


use  the  spirits  diluted,  because  the  lead  niter  is  not 
soluble  in  the  concentrated  spirits.  When  all  of 
the  lead  oxyd  is  thus  dissolved,  or  when  the  liquid 
will  not  further  dissolve  the  oxyd,  filter  and  evap- 
orate the  filtrate  to  complete  dryness.  The  residue  is 
then  pure  lead  niter.  Heated  in  a  crucible  or  glass 
tube,  the  lead  niter  breaks  up  into  brown  gas  and 
yellow  lead  oxyd.  The  brown  gas  is  very  acrid 
and  suffocating,  yet  it  will  act  upon  a  glowing  taper 
like  oxygen.  In  fact  we  can  readily  prove  the 
brown  fumes  to  have  an  admixture  of  oxygen  ; 
therefore 

Pb(NmO)2  +  heat  =  PbO  -f  brown  gas  +  0. 
This  action  opens  the  way  for  a  quantitative  deter- 
mination of  the  ratio  existing  between  Pb,  N  and 

FIG.  45. 


0,  if  we  arrange  the  conditions  of  the  experiments 
in  such  a  way  that  the  volume  of  nitrogen  can  be 
accurately  measured,  which  results  from  the  decom- 
position of  say  one  gram  of  the  lead  niter. 

Let  T,  Fig.  45,  be  an  ample  hard  glass  tube  fitted 
11 


162  CHEMISTRY    SIMPLIFIED. 

with  stoppers.     8  is  a  porcelain  boat  containing  0.5 
gram  of  lead  niter.     9  is  a  clean  roll  of  copper 
gauze.     7  is  a  U-tube  filled  with  pieces  of  pumice 
and  H2S04   (to  retain  moisture).     6  is  a  smaller 
U-tube  with  enough  H2S04  to  form  a  trap.     H is 
the  holder  filled  with  lime  gas  and  the  water  in  B 
furnishes  the  pressure  to  drive  out  the  gas  from  H. 
10  is  a  gas  burette  and  11  the  cylinder  to  regulate 
the  pressure.     Both  cylinders  are  filled  with  solu- 
tion of  sodium  hydrate.     All  stoppers  and  connec- 
tions being  tight,  we  first  displace  all  air  from  the 
apparatus,  because  four-fifths  of  it  are   nitrogen ; 
then  heat  the  copper  gauze  to  redness,  while  we 
protect  the  boat  from  the  heat  by  the  shield  12. 
When  the  gauze  is  glowing  we  move  shield  12  to 
the  left,  from  time  to  time,  so  that  the  decompo- 
sition of  the  lead  niter  shall  be  slow  and  gradual ; 
but  at  length  the  entire  tube  is  at  redness  up  to  the 
shield.     As  the  niter  decomposes  the  oxygen  goes  to 
the  copper  and  the  nitrogen  passes  into  the  burette, 
pushing  before  it  the  lime  gas.     As  soon  as  the  con- 
tents of  the  boat  are  pure  dark  yellow  or  red,  we 
open  the  stop  cock  4-  and  drive  all  niter  gas  into  the 
burette.     Then,    closing   the   latter's   stopcock,   we 
shake  the  gas  with  the  liquid,  thus  absorbing  all  the 
lime  gas  into  the  Na(OH)  solution,  and  then  read 
the  volume  of  gas.     Let  V  cubic  centimeters  be  the 
volume  of  the  gas,  measured  under  the  pressure  of 
the  atmosphere  at    20°  C,  the  pressure  of  the  at- 
mosphere, measured  by  the  mercury  column  of  the 
barometer,  be  B  millimeters.     As  the  gas  is  satur- 


LECTURE  ON  NITER  OR  SALTPETER.     163 

ated  with  aqueous  vapor,  being  over  water,  i.  e.,  a 
dilute  solution  of  Na(HO),  the  tension  T  of  the 
aqueous  vapor  increases  the  pressure  B  and  must 
therefore  be  subtracted,  because  we  wish  to  get  at 
the  volume  of  the  di~y  gas.  The  expansion  of  the 
air  for  one  degree  C.  is  0.00367  of  its  volume,  hence 
the  volume  V°  of  dry  gas  at  0°  C.  and  sea  level  bar- 
ometer, 760  mm.,  will  be 

V'.(B  —  T) 

=  (1  +  0.00367t)  X  760  = 

(The  tables  calculated  by  Prof.  Leo  Liebermann  are 
most  convenient  in  such  calculations.)  If  the  weight 
of  one  c.c.  of  dry  nitrogen  at  0°  C.  and  760  mm.  be 
0.001256  gram,  then 

V°  X  0.001256  =  G, 

will  be  the  weight  of  the  nitrogen  contained  in  0.5 
gram  of  lead  niter,  Pb(NmO)2.  G  equals  0.0423 
gram  and  the  weight  of  lead  oxyd,  PbO,  is  0.337 
gram  (found  by  weighing  boat  after  operation). 
Then  we  will  have 

PbO  =  0.3370 

N       =  0.0423  }  =  0.163  gram  ==  wt.  of  the  N. 

0       =  0.1207  /         oxyd. 

0.5000     - 

The  weight  of  oxygen  if  found  by  difference.  The 
volume  weights  of  oxygen  and  nitrogen  (found  by 
direct  weighing)  are  16  and  14.  Hence  we  will  ob- 
tain the  atomic  ratio  of  the  two  elements  by  divid- 
ing gram  weights  of  N  and  0  by  14  and  16  respec- 
tively. 


164  CHEMISTRY    SIMPLIFIED. 

2^23=0.00302; -2^07  =  0.00754  I 

14  16 

302        2 

754  -=  5>  hence  N2°5 

We  have  directly  proved  that  lead  niter  is  a  combi- 
nation of  the  oxyd  PbO  with  the  oxyd  N206. 
Above  we  showed  the  probability  of  the  radical 
NmOp  being  a  monad.  In  the  lead  niter  there  are 
then  two  molecules  of  the  nitric  radical. 

PbO.N205  becomes  Pb(N206)  or  Pb(N03)2. 
For  the  sake  of  uniformity  we  will  designate  here- 
after the  niters  by  the  word  nitrate,  thus : 

Hydrogen  nitrate  =  H(N03)  =  nitric  acid  =  aqua 
fortis. 

Sodium  nitrate  =  Na(N03)  =  soda   niter  =  Chili 
niter. 

Potassium   nitrate  =  K(N03)  =  potash   niter  =• 
common  niter. 

Calcium  nitrate  =  Ca(NO3)2. 

Silver  nitrate  —  Ag(N08). 

Lead  nitrate  =  Pb(N03)2. 

Copper  nitrate  =  Cu(N03)2. 

Ferric  nitrate  =  Fe(N03)3. 

All  normal  nitrates  are  soluble  in  water,  whilst  some 
sulfates,  some  chlorids,  bromids,  iodids,  fluorids  are 
insoluble  in  water. 

Sol.    Ag(N03)  +  sol.    NaCl  =  insol.    AgCl  +  sol. 
Na(N03). 


LECTURE  ON  NITER  OR  SALTPETER.     165 

Sol.  Pb(N03)2  -f  sol.  Na2(SO4)  =  insol.  Pb(S04) -f 

sol.  2Na(N03). 

These  two  reactions  serve  us  as  tests  for  soluble  chlo- 
rids  and  sulfates  respectively. 

Of  all  bodies  we  have  investigated,  the  nitrates 
appear  to  me  the  most  wonderful.  The  very  same 
elements  in  which  we  breathe  and  lead  a  more  or 
less  harmless  life,  the  existence  of  which  elements 
we  are  not  even  ordinarily  aware  of,  become  vio- 
olently  active  in  the  form  of  nitrates.  The  chlo- 
rates, though  acting  similarly,  are  not  so  astonish- 
ing, because  in  them  we  find  chlorine,  a  violently 
offensive  body  by  itself.  A  rather  rough  simile 
may  bring  nearer  to  your  grip  of  imagination  this 
action  of  the  nitrates.  Let  the  atoms  be  imagined 
as  spiral  springs  (watch  spirals).  In  the  atmos- 
phere the  nitrogen  molecules  lie  alongside  of  the 
oxygen  molecules  as  uncoiled  springs,  inert,  inoffen- 
sive things.  A  powerful  shock  strikes  the  inert, 
uncoiled  bodies,  say  the  electric  spark  of  a  thunder 
storm ;  the  shock  causes  the  springs  to  coil  up,  and 
the  affinity  of  a  strong  basic  oxyd,  as  K20,  Na20,  lies 
handy  as  a  binding  rope  of  the  springs,  as  shown  in 
Fig.  46  ;  the  nitrate  molecule  is  achieved  ;  the  poten- 
tial energy  of  the  coils  is  restrained  by  the  thin 
band  of  affinity.  Now  let  the  nitrate  molecules  be 
brought  into  intimate  contact  with  other  molecules 
which  possess  a  stronger  affinity  for  oxygen  than 
the  nitrogen,  for  instance,  carbon  molecules,  at  a 
red  heat.  We  may  even  carry  the  picture  further 
and  say  the  thermic  energy  expands  the  springs, 


166  CHEMISTRY    SIMPLIFIED. 

straining  them  against  the  restraining  bond  until 
at  red  heat  this  bond  snaps,  giving  way  to  carbon 
— oxygen  attraction.  With  the  breaking  of  the 

FIG.  46. 


Na-K-Ca 


bond,  the  oxygen  springs  uncoil  and  display  an 
extraordinary  energy,  such  as  we  are  forced  to  ad- 
mire in  gunpowder. 

COMPOSITION    OF   GUNPOWDER    OR    BLACK    POWDER. 

We  saw  in  a  small  experiment  how  the  mixture 
of  niter  and  charcoal  powder  flew  out  of  the  glass 
tube  with  a  flash.  The  products  of  that  action  were 
Na2(C03),  sodium  carbonate,  N,  nitrogen  and 
CO2.  The  two  latter  gases,  through  their  expan- 
sion, impart  to  the  explosion  its  propelling  or  its 
tearing,  splitting  effect.  The  more  gas,  the  greater 
the  effect  from  a  given  mixture.  But  in  forming 
Na2C03  much  gas  passes  into  the  solid  state  and 
lessens  the  effect  of  the  powder.  It  was  soon  found 
that  a  greater  effect  could  be  obtained  by  mixing 
with  niter  and  charcoal  a  certain  quantity  of  sulfur. 
This  was  all  arrived  at  by  those  patient  experi- 
menters without  knowing  even  that  the  production 
of  gas  was  the  chief  object.  They  mixed  sulfur 


LECTURE    ON    NITER    OR    SALTPETER.  167 

with  the  powder  on  general  principles  that  it  would 
be  a  good  thing,  because  sulfur  was  a  very  peculiar 
and  mysterious  body.  We  modern  chemists,  who 
experiment  less  and  think  more,  know  why  the  sul- 
fur increases  the  effect.  This  is  the  theoretical  pic- 
ture of  the  explosion  : 

2K(N03)  +  S  +  3C  -f  red  heat  =  K2S(solid)  + 

2N  +  3C02. 
By  weight 
2(39  + 14  +  48)  -f  32  -f  3  X.12  =  2  X  39  +  32(solid) 


202  +32+     36     =  110 

+  2x14  +  3(12  +  32) 

+    28     +          132 

KNO8  =  202  =  74.81  %  75  potassium  niter 

S  =    32  =  11.85  12  sulfur 

C          =    36  =  13.34  13  fine  charcoal 


270     100.00 

On  the  second  side  of  the  equation  stand 
K2S   ==110=   40.70^  (solid)    41  solid 
2N      =    28-     10.40  f.  gas         10 


3C02=132=    48.90  <&  gas  ^ 


270       100.00. 

59  per  cent,  of  the  powder  is  converted  into  gas. 
One  gram  of  the  powder  gives  by  the  explosion  0.1 
gram  of  nitrogen,  0.49  gram  of  carbon  dioxyd.  At 
0°  C.  and  700  mm.,  0.001256  gram  of  nitrogen  occu- 


168  CHEMISTRY    SIMPLIFIED. 

pies  the  space  of  one  c.c.;  0.1  gram  of  nitrogen  occu- 
pies the  space  of  79.6  c.c.  0.001977  gram  CO2 
occupies  the  space  of  1  c.c.;  0.49  gram  CO2  the  space 
of  247.3  c.c.  The  volume  of  gas  produced  by  the 
explosion  of  one  gram  of  perfect  black  powder  is  at 
0°  C,  247.3  +  79.6  =  326.9  c.c.  One  gram  of  best 
powder,  in  small  but  perfect  angular  grains,  occu- 
pies the  space  of  0.9  c.c.;  the  surface  of  1  c.c.  being 
six  square  centimeters.  Hence  if  one  gram  of  such 
powder  be  filled  into  a  cartridge  and  a  bullet  be 
pressed  tightly  upon  the  powder,  a  space  will  be 
filled  possessing  six  times  0.9  —  5.4  square  centi- 
meters. After  explosion  this  same  space  will  be 
filled  with  326.9  c.c.  of  gas  which  will  press  upon 

326  9 
the  enclosing  surface  with    Q  Q    —  363.2  times  the 

pressure  of  the  atmosphere  or  upon  1   square  centi- 

363.2 
meter  with     ^  *    =  67.26  atmospheres.      But  there 

is  another  very  important  factor ;  the  heat  gener- 
ated by  the  explosion,  which  expands  the  gas  merci- 
lessly, and  if  the  enclosure  be  rigid,  exerting  an 
ever-increasing  pressure.  The  gases  expand,  within 
certain  limits  so  nearly  alike,  that  one  coefficient 
answers  for  all.  This  coefficient  is  yfs  or  0.00367 
volume  for  1°  C.  By  the  following  reasoning  we 
arrive  at  the  theoretical  temperature  produced  by 
the  explosion  of  one  gram  of  powder :  1  gram  car- 
bon through  the  oxydation  into  CO2  produces  heat 
equal  to  8050  calories  (the  heat  would  raise  the 
temperature  t  of  8050  grams  of  water  by  one  de- 


LECTURE    ON    NITER    OR    SALTPETER.  169 

gree  C.  Hence  0.13  gram  of  carbon  will  produce 
8050  X  0.13  =  1046  calories.  By  the  burning  have 
been  produced  0.49  gram  of  CO2,  0.1  gram  of  N  and 
0.41  of  K2S.  Each  of  these  bodies  has  a  capacity 
for  heat  to  be  swallowed  up  before  the  heat  can  be 
felt.  The  temperature,  the  sensible  heat,  must 
therefore  be  directly  proportional  to  the  absolute 
heat  —  the  1046  calories,  and  inversely  to  the  ab- 
sorbed heat.  In  a  general  way 

A 

T°  _  fz 

a 

in  which  A  =  absolute  heat,  a  =  weight  of  pro- 
ducts into  their  respective  specific  heats. 
In  our  special  case 

TO_  _  1046  __ 

0.499  X  0.22  -f  0.1  X  0.24  +  0.41  X  0.4 

1046  1046 


0.108+0.024+0.164      0.296 

The  a  in  the  denominator  is  represented  by  the  sum 
of  the  products  of  the  combustion  of  the  powder  ; 
each  member  multiplied  by  its  factor  representing 
the  unit  of  heat  capacity  or  specific  heat. 

Thus  it  is  seen  that  by  the  combustion  of  one 
gram  of  powder  a  temperature  is  generated  equal  to 
3534°  C.,  higher  than  that  of  an  intense  coal  fire. 
At  this  temperature  the  326.9  c.c.  of  gas  must  have 
expanded  to  326.9  X  0.00367  X  3535  =  4236.6  c.c., 
to  12.9  times  their  volume  at  0°  C.,  or  871.7  atmos- 
pheres pressure  per  sq.  cm.,  provided  the  law  of  ex- 
pansion holds  good  at  such  high  temperature,  but 


170  CHEMISTRY    SIMPLIFIED. 

this  is  by  no  means  certain.  At  any  rate,  the  theo- 
retical picture  gives  a  measure  for  the  actual  phe- 
nomenon. We  see  that  the  pressure  of  the  gas  must 
be  enormous,  though  less  than  the  theoretical,  in 
fact  only  about  J  as  shown  by  actual  experiment, 
made  for  the  military  departments  of  several  gov- 
ernments. Such  experiments  are  known  by  the 
adjective  ballistic  (made  with  a  ball).  The  reasons 
are  several.  In  the  first  place  the  burning  of  the 
powder  is  never  complete.  2.  The  reactions  are  not 
quite  like  the  formula  indicates.  A  part  of  the 
oxygen  remains  fixed  by  forming  K2S04,  hence 
some  of  the  carbon  only  burns  to  CO,  whilst  some 
of  the  nitrogen  remains  as  NO.  3.  The  material  of 
the  apparatus — a  gun  for  instance,  or  a  mortar — is 
somewhat  elastic. 

As  engineers  we  should  know  all  that  has  here 
been  given,  to  understand  the  effects  of  the  blasting 
powder  we  use.  I  give  you  only  the  chemical  facts 
connected  with  the  matter. 

Other  powders.  The  white  and  smokeless  powders 
all  contain  a  nitric  radical,  either  NO2  or  NO3.  In 
principle  there  is  no  difference  between  them  and 
black  powder.  Their  special  compositions  will  be 
dealt  with  under  the  subject  of  carbon  compounds. 

INVESTIGATION    OF    THE     BROWN    FUMES    OR    NITROUS 

FUMES. 

These  always  form,  when  H(N03)  acts  upon  an 

oxydizable  substance,  as  copper  for  instance,  or  SO2. 

Acting  with  H(N03)  upon  copper  in  a  test-tube 


LECTURE  ON  NITER  OR  SALTPETER.     171 

we  observe  the  tube  filled  with  the  brown  fumes  so 
long  as  the  action  continues.  But  if  the  tube  be 
stoppered  with  a  narrow  tube  for  the  escape  of  the 
gases,  a  different  action  ensues.  We  notice  that  the 
gas  inside  the  tube  turns  lighter  by  degrees,  at  last 
being  quite  colorless,  but  at  the  mouth  of  the  escape 
tube  a  steady  cloud  of  dense,  brown-colored  gas  is 
visible  all  the  time.  This  at  once  suggests  the  pres- 
ence of  two  different  gases  within  the  brown  fumes. 
More  precisely  we  would  say  :  Through  the  action 
of  HNO3  upon  an  oxydizable  body  is  generated  a 
colorless  gas — an  oxyd  of  nitrogen.  When  this 
gaseous  oxyd  comes  together  with  air  the  brown  gas 
forms  by  combination  of  the  air-oxygen  with  the 
colorless  gas  ;  but  the  brown  gas  itself  must  possess 
a  ratio  of  oxygen  to  nitrogen  less  than  5/2,  for  if  it 
is  absorbed  in  ice  water  we  find  produced  a  mixture 
of  spirits  of  niter  and  the  same  acid  that  was  made 
by  acting  with  H2S04  on  the  residue  left  after  heat- 
ing niter.  All  this  will  be  proved  presently.  The 
brown  gas  becomes  colorless  if  mixed  with  an  oxy- 
dizable body,  as  SO2  for  instance,  evidently  by  loss 
of  oxygen.  Hence  the  colorless  gas  must  have  an 
oxygen  to  nitrogen  ratio  less  than  the  brown  gas. 

Nitrogen  dioxyd,  NO2  or  N204,  hyponitric  anhy- 
drate  the  nitrous  fumes.  Let  the  tube  T,  Fig.  47,  be 
partly  filled  with  dry  lead  nitrate  and  placed  in 
furnace  F.  Make  the  U-tube  U  from  a  J"  tube, 
draw  it  out  into  a  capillary  at  C,  a  and  6,  then  sur- 
round it  in  the  basin  B  with  a  mixture  of  ice  and 
coarse  common  salt ;  stick  a  thermometer  t  into  the 


172  CHEMISTRY    SIMPLIFIED. 

mixture.  If  the  salt  be  kept  on  snow  or  ice  until 
its  temperature  falls  to  0°  C.,  and  if  it  be  then  mixed 
with  one  volume  of  snow  or  fine-cut  ice,  the  tem- 
perature of  the  basin  will  drop  to  — 20°  C.  Make 

FIG.  47. 


connection  at  C  with  T,  and  heat  T  to  redness  grad- 
ually.    We  know  from  previous  experiment  (com- 
position of  N205)  that  the  Pb(N03)2  breaks  up  into 
PbO  -f-  brown  fumes.     Thus 
Pb(N03)2  -f-  heat  =  PbO  +  (NmO-x)  brown  fumes 

+  (6— p— x— 1)0. 

Passing  into  U  the  fumes  condense  into  a  brown 
liquid  and  at  6  issues  a  gas  which  sustains  combus- 
tion with  energy — (oxygen).  At  end  of  decomposi- 
tion close  U  at  C  and  a  with  the  blow-pipe.  If  the 
U-tube  be  changed  twice,  then  you  find  in  the  third 
tube  colorless  crystals.  These  represent  the  true 
substance.  The  crystals  melt  at  — 12°  C.  to  a  color- 
less or  slightly  yellow  liquid.  It  follows  that  no 
crystals  result  if  the  temperature  of  the  freezing 
mixture  be  not  at  the  least  — 15°  C.  As  the  liquid 
is  heated  by  the  warmth  of  the  hand  it  becomes 
more  and  more  highly  colored,  giving  out  dense 
brown  fumes  and  reaches  a  constant  boiling-point 


LECTURE  ON  NITER  OR  SALTPETER.      173 

at  -j-22°  C.  (in  the  hand,  because  the  temperature 
of  the  blood  is  33°  C.).  On  the  addition  of  ice 
water  drop  by  drop,  the  liquid  turns  first  green,  then 
blue,  then  colorless.  It  acts  upon  oxydizable  bodies 
more  energetically  than  HNO3,  because  the  restrain- 
ing bond  of  the  hydrogen  is  removed.  Mention  has 
already  been  made  of  the  suffocating  action  of  the 
brown  fumes.  The  living  organism  tries  to  avoid 
the  danger  lurking  in  the  breathing  of  the  gas, 
for  the  muscles  of  the  epiglottis  contract  instantly 
when  the  gas  comes  in  contact  with  their  nerve 
ends.  At  Berlin,  some  years  ago,  fire  broke  out  in 
the  yard  of  a  large  chemical  works.  Sixty  carboys 
of  aqua  fortis  were  stored  under  one  shed.  They 
exploded,  one  by  one.  The  acid  flowing  into  the 
straw  and  wood  of  the  packing  let  out  an  immense 
volume  of  brown  fumes.  Five  of  the  firemen  who 
had  been  endeavoring  to  save  the  carboys,  went 
back  to  the  station  with  the  others,  smoked  a  pipe 
and  went  to  sleep  in  their  bunks.  Within  a  few 
hours  they  woke  in  convulsions  and  died  shortly 
after,  in  great  agony.  Let  this  be  a  warning  to  be 
careful.  Do  not  act  upon  metals,  or  sulfids  with 
HNO3,  except  in  a  well-drawing  hood;  for  even  if 
death  does  not  ensue,  there  may  be  permanent  in- 
jury to  the  bronchise  and  their  capillary  ramification 
in  the  lungs,  from  ulceration  of  the  mucous  mem- 
brane. The  composition  of  the  brown  gas  we  find 
similarly  to  that  of  the  lead  niter.  We  make  a  small 
U-tube  U,  Fig.  48,  drawn  out  into  capillary  thread 
at  a,  b.  We  take  the  weight  and  then  fill  into  it  a 


174  CHP:MISTRY  SIMPLIFIED. 

few  drops  of  the  liquid,  by  pressure  or  by  suctioD. 
In  T  there  is  the  coil  of  copper  wire.  At  B  is  the 
burette  for  measuring  the  gas,  filled  with  solution 
Na(HO),  and  which  is  immersed  in  a  dish  of  water 

FIG.  48. 


when  in  use.  We  fill  the  tube  T  with  lime  gas,  in- 
sert £7  at  b  into  the  stopper  and  a  into  rubber  tube 
leading  to  lime  gas  holder  and  furnished  with 
clamps  C;  then  connect  the  burette  B.  We  bring 
T  up  to  redness  and  turn  on  the  lime  gas  in  a  gentle 
current.  The  radiant  heat  will  suffice  to  volitalize 
the  liquid  oxyd  of  nitrogen  and  the  lime  gas  will 
carry  it  over  the  copper  gauze.  Nitrogen  and  lime 
gas  pass  into  B  and  the  NaHO  solution  will  absorb 
the  lime  gas.  Thus  we  get  the  nitrogen  volume 
which  we  deal  with  as  in  the  previous  experiment ;  w 
being  weight  of  oxyd,  n  being  the  weight  of  nitro- 
gen, w  —  n  =  0,  the  weight  of  the  oxygen.  Divid- 
ing n  by  14  and  w  —  n  by  16,  we  get  the  ratio 

Jl  :  w~n  =  1  :  2  =  NO2  or  N204  or  N408 
14        16 

Some  investigators  claim  the  ratio  N408  which  can 
be  interpreted  as  N203.N205  a  combination  of  the 
two  oxyds,  on  the  ground  that  when  ice  water  be 


LECTURE  ON  NITER  OR  SALTPETER.     175 

mixed  with  the  liquid  oxyd  it  breaks  up  into  the 
two    acid    bodies:    H(N02),    hydrogen   nitrite   and 
H(N03),  hydrogen  nitrate :  to  wit 
N203  -f-  H20  =  2H(NO)2;  N205  +  H20  =  2H(N08) 
However,  this  view,  which  looks  at  the  molecule  as  a 
polymeric  molecule,  i.  e.}  4  times  NO2,  only  applies 
at  low  temperatures,  for  Dulong  found  for  the  brown 
gas  the  specific  gravity  1.62,  and  this  corresponds  to 
\  vol.  nitrogen  —  0.4856 
1  vol.  oxygen  =  1.105 

L5906 

so  nearly  1.62  that  we  can  have  no  doubt  left.  The 
new  gaseous  molecule  is  surely  NO2  =  2(JN  -{-  0). 
1  vol.  N  -f  2  vols.  O  =  3  vols.,  become  2  vols. 
NO2;  there  is  a  condensation  of  3:2  of  1J:1. 

When  the  brown  fumes  are  passed  into  H2(S04), 
the  fumes  become  absorbed,  and  if  the  operation  be 
continued  for  a  time,  colorless  crystals  form  in  the 
acid.  The  crystals  are  obtained  more  readily  by 
pouring  a  few  cubic  centimeters  of  H2(S04)  into  a 
small  flask  and  by  spreading  the  liquid,  through 
rotation,  upon  the  entire  glass  surface.  If  now  the 
brown  fumes  are  brought  into  the  bottom  of  the 
flask,  under  the  rotation  the  brown  fumes  become 
absorbed,  a  crystalline  crust  resembling  ice  forming 
all  over  the  flask  (inside).  The  composition  is  not. 
definitely  settled,  probably  2H2(SO4).N02.  The 
reaction  is  of  much  economical  importance  in  the 
manufacture  of  H2(S04)  on  a  large  scale  and  will 
be  brought  forward  when  we  shall  arrive  at  that 
process. 


176  CHEMISTRY    SIMPLIFIED. 

The  colorless  gas,  nitrogen  monoxyd,  nitric  oxyd,  NO. 
This  body  becomes  generated  whenever  H(N03)  acts 
upon  oxydizable  bodies,  metals,  metallic  sulfids, 
paper,  wood,  sulfur  dioxyd.  As  soon  as  it  comes 
into  contact  with  the  air  it  changes  into  nitrogen 
dioxyd  NO2  (brown  nitric  fumes).  We  obtain  this 
gas  very  pure  by  passing  SO2  into  warm  HNO*  -f 
water. 

In  flask  F,   Fig.   49,  we  generate  SO2  from  the 

FIG.  49. 


mixture  M,   which  is  copper  gauze   and    H2S04, 
heated  by  a  flame,  according  to  equation 

Cu  +  2H2(S04)  =  CuSO4  +  2H20  +  SO2. 
Through  tube  1  gas  passes  into  the  washing  tube  #, 
partly  filled  with  H2(S04)  (moisture  is  retained  and 
flow  of  gas  can  be  regulated).  IF  is  a  so-called 
Will's  condenser,  possessing  the  three  bulbs,  5,  4,  5, 
and  containing  2H(N03)  -f  2H20.  B  is  a  basin 
holding  warm  water  to  heat  the  H(N03);  through 
tube  6  the  gas  can  be  delivered  into  any  suitable 
vessel.  In  the  figure  this  vessel  is  a  knee-tube  T 
filled  with  mercury  and  standing  in  mercury  trough 
Q.  T  is  held  by  stand  S.  When  the  gas  SO2  bub- 
bles into  the  H(N08)  it  becomes  oxydized  into 


LECTURE  ON  NITER  OR  SALTPETER.     177 

H2(S04)  and  H(N03)  becomes  changed  into  the 
nitrogen  monoxyd. 

Thus  3S02  +  2H(N08)  +  2H2O  =  3H2S04  + 

2NO  (colorless  gas). 

Do  not  think  the  composition  of  the  gas  must  be 
NO,  because  the  equation  demands  it,  many  stu- 
dents, and  even  some  professors,  have  that  belief.  I 
wrote  the  equation  because  I  know  the  gas  to  be 
NO.  I  could  have  balanced  the  equation  in  several 
other  ways,  merely  by  changing  the  coefficients  of 
SO2  and  ofHNO3. 

Proof  of  the  composition  of  nitrogen  monoxyd.  Sup- 
pose we  have  allowed  to  enter  into  the  knee-tube 
T,  Fig.  49,  about  10  c.c.  of  the  gas  and  have  marked 
this  volume  by  a  sticker.  Banking  upon  the  known 
maximum  of  affinity  of  potassium  for  oxygen,  we 
will  introduce,  by  means  of  a  thin  copper  wire,  a 
piece  of  metallic  potassium  at  P,  and  heat  the  metal 
with  a  burner.  A  flash  of  light  and  a  violent  com- 
motion of  the  gas  accompany  the  act  of  deoxydation 
of  the  gas.  I  must  hold  the  tube  firmly,  with  the 
left  hand,  to  prevent  its  being  raised  above  the  mer- 
cury level  in  Q.  When  the  tube  has  resumed  the 
temperature  of  surrounding  air  we  find  the  volume 
of  gas  shrunk  to  exactly  J  ;  hence  there  is  in  one 
volume  of  nitrogen  monoxyd  J  vol.  N  -f-  J  vol.  0 
or  made  into  full  units  1  vol.  N  -f  1  vol.  0,  the  sym- 
bol of  the  gas  is  NO.  There  is  no  contraction  in 
the  union. 

Specific  gravity  of  NO  found  by  weighing  1  vol. 
=-1.0379  (air=l) 
12 


178  CHEMISTRY    SIMPLIFIED. 

J  vol.  N  =  0.4856 

j  vol.  0  =  0.5525 
L0381 

Calculated  specific  gravity  equal  to  the  experi- 
mental, hence  NO  represents  the  molecular  volume 
of  the  gas. 

Properties  of  NO.  The  gas  cannot  occur  in  nature. 
Why?  Because  it  changes  to  NO2  on  meeting  the 
oxygen  of  the  air.  For  the  same  reason  we  do  not 
know  whether  it  has  odor^or  taste.  Does  not  act  on 
litmus  paper.  Its  actions  on  the  breathing  organs 
are  the  same  as  those  of  NO2,  for  the  same  reason  as 
above.  If  the  gas  be  conducted  into  a  solution  of 
copperas  Fe(S04)  +  7H20  or  Fe(Cl2)  +  2H20  the 
solution  turns  dark  brown,  or  even  inky  black.  The 
gas  is  completely  absorbed.  Distinction  from  all 
other  gases.  This  reaction  enables  us  to  recognize 
and  identify  a  nitrate  in  an  unknown  mixture,  even 
.very  minute  quantities  of  the  nitrate.  Proceed  as 
follows  with  this  test :  Bring  the  unknown  solution 
(1  c.c.)  into  the  bottom  of  a  test-tube  T,  Fig.  50,  add 
2  c.c.  of  concentrated  H2(S04)  and  mix.  Then 
take  into  a  glass  tube  t,  which  has  been  drawn  out 
to  a  capillary,  a  strong  solution  of  copperas  (ferrous 
sulfate)  Fe(S04).  Lower  t  into  T,  so  that  the, point 
just  touches  surface  of  the  liquid  mixture,  and  let 
run  out  a  few  cubic  centimeters.  The  two  liquids 
are  then  unmixed,  in  two  superimposed  strata. 
Within  a  short  time  a  dark  ring  will  develop  at  the 
contact  of  the  strata.  If  no  dark  ring  develops  then 
the  unknown  substance  does  not  contain  any  nitrate. 


LECTURE   ON   NITER   OR   SALTPETER. 


179 


The  student  should  practice  this  reaction  using  as 
unknown  a  solution  which  was  made  up  from  one 
drop  of  strong  H(N03)  and  50  c.c.  of  water  (ap- 
proximately 0.2  per  cent.  HNO3). 

Nitrites,  Na(NO*),  K(NO*),  Ag(N02).  Di-nitrogerti- 
trioxyd,  N20*.  Both  -Na(N08)  and  K(N03)  loose 
oxygen  when  heated  at  low  red  heat  and  more 
rapidly  at  bright  red  heat.  Since  neither  the  metal 

FIG.  50. 


nor  nitrogen  is  given  off,  the  ratio  between  the 
three  elements  must  become  changed  ;  a  new  body 
forms.  This  we  can  demonstrate  readily  in  two 
ways  :  (1)  by  acting  upon  the  residue  with  concen- 
trated H2S04  when  copious  brown  fumes  are  given 
off;  (Recall  that  the  nitrates  +  H2S04  do  not  give 


180  CHEMISTRY    SIMPLIFIED. 

any  fumes.)  (2)  by  adding  solution  of  Ag(N03)  to 
the  water  solution  of  the  residue — a  white  precipi- 
tate falls  out,  which  is  not  very  soluble  in  water. 
This  silver  salt  does  not  contain  water,  and  by  its 
decomposition  we  can  find  the  ratio  of  Ag,  N,  0,  by 
using  the  apparatus  and  method  followed  with  the 
lead  nitrate.  Let  the  silver  salt,  which  shall  be 
named  silver  nitrite  (note  the  substitution  of  the 
letter  i  for  the  letter  a  in  nitrate)  be  Ag(NmQP~q) 
then  we  shall  obtain  by  the  decomposition 

Ag(NmOp~q)  -f-  red  heat  =  Ag  +  brown  fumes. 
Let  the  fumes  be  decomposed  by  copper  gauze  at 
red  heat  and  you  get  the  nitrogen. 

(NmQp-q)  fumes  _|_  aCu  _|_  re(j  heat  =  (p_q)CuO  + 
(a-p-q)Cu  +  mN  and  thus  we  find  : 

Ag  :  N  :  0  —  1  :  1  :  2  hence  the  formula  of  the 
nitrite  is 

Ag(N02)  and  similarly  must  be  the  Na,  K  salt 

Na(N02) 

K(N02) 
The  hydrogen  salt  cannot  be  made,  it  is  too  unstable. 

Preparing  K(N02).     Heat  niter  in  an  iron  pot  or 
crucible  to  melting  heat,  then  add  2  parts  of  metallic 
lead  for  each  part  of  niter.     The  affinity  of  lead  for 
oxygen  helps  the  decomposition  of  the  niter  : 
K(N03)  -f  heat  +  Pb  =  K(N02)  +  PbO 

Molecular  weight  K(N03)  =  101,  atomic  weight  of 
Pb  =  207,  hence  1  part  niter  -f-  2  parts  lead,  corre- 
spond to  theory.  In  practice,  however,  the  reac- 
tions are  not  complete.  Some  lead  is  apt  to  remain 


LECTURE    ON    NITER    OR    SALTPETER.  181 

unoxydized,  some  oxygen  escapes,  the  residue  is, 
usually,  K(NO2)  mixed  with  PbO,  KNO3  and  K2O. 
Dissolve  the  fused  mass  in  little  boiling  water  and 
let  cool.  The  PbO  will  settle,  the  K(X03)  will 
crystallize.  Decant  (that  is  pour  off)  the  liquid  and 
evaporate  to  dryness,  finally  heat  to  melting  and 
pour  into  pencil  moulds,  same  as  used  for  NaOH 
and  KOH.  K(X02)  is  a  reagent  in  use  for  the 
separation  of  cobalt  from  nickel,  as  well  as  for  other 
operations.  The  salt  usually  shows  an  alkaline  re- 
action from  KOH,  can  be  neutralized  with  dilute 
acetic  acid. 

In  the  nitrites,  we  have  undoubtedly  a  peculiar 
oxyd  of  nitrogen.  The  radical  (NO2)  is  not  that 
oxyd,  its  reactions  are  quite  different.  This  oxyd 
is  X203,  for  K2O.X203  =  2K(X02)2.  This  oxyd 
— dinitrogen  trioxyd — is  contained  in  the  brown 
fumes,  as  gas.  It  may  be  condensed  at — 15°  C. 
into  a  deeply  blue  liquid,  which  boils  even  at  the 
freezing-point  of  water.  A  blue  solution  results  from 
the  action  of  XO  gas  upon  a  solution  of  H(X03)  in 
water  (specific  gravity  =  1.25)  a  green  solution,  when 
the  specific  gravity  is  1.35  (because  this  liquid  then 
contains  both  X203  and  X204,(2X02).  The  same 
colors  result  when  acids  of  the  given  specific  gravi- 
ties act  upon  certain  oxidizable  bodies.  Any  one 
not  knowing  this  fact  will  often  waste  much  time 
trying  to  find  copper  (blue  nitrate)  because  he  sees 
a  blue  solution,  or  chromium  because  he  sees  a  green 
solution  when  acting  on  galena,  the  lead  sulfid,  for 
instance.  The  student  should  get  this  information 
by  experiment  to  fasten  it  the  more  firmly. 


182  CHEMISTRY    SIMPLIFIED. 

If  a  solution  of  Na(N03)  or  K(N03)  be  shaken 
with  amalgamated  zinc  (zinc  coated  with  mercury) 
the  solution  will  then  contain  nitrite,  to  be  detected 
by  the  addition  of  the  liquid  to  starch  paste  contain- 
ing potassium  iodid  and  some  free  H2S04  (dilute). 
The  paste  turns  blue,  because 
KI  +  H2S04  (dilute)  +  NaNO2  =  1  +  NajK(S04)+ 

IPO  +  NO. 

The  rain  water  from  a  thunder  shower  will  give 
this  reaction,  showing  that  it  contains  nitrite;  azote 
and  oxygen  have  become  united  by  the  electric  dis- 
charges of  the  storm. 

Dinitrogen  monoxyd,  N2  0,  nitrous  oxyd,  laughing- 
gas.  This  gas  arises  when  the  monoxyd  NO  is  al- 
lowed to  stand  in  contact  with  easily  oxydizable 
substances ;  finely  divided  zinc,  iron  filings,  sulfites 
(Na2(S03)),  and  many  others.  One-half  of  the  oxy- 
gen is  removed,  or  2  molecules  NO  furnish  one 
molecule  N20. 
Thus  2NO  +  Zn  =  N20  +  ZnO 

2NO  -f  Na2(S03)  —  N20  +  Na2(S04). 
We  proceed  to  prove  this  by  acting  with  heated 
potassium  upon  the  gas  in  a  knee-tube,  exactly  as 
described  for  NO.  The  action  is  quite  as  energetic. 
After  cooling  the  volume  is  the  same  as  before  the 
action.  Hence  one  volume  gas  contains  one  volume 
nitrogen.  Weight  of  one  vol.  gas  (spec,  gr.)  =  1.5270 
minus  weight  of  one  vol.  N  (spec.gr.)  =  0.9713 

05557 
but  0.5557  is  very  near  L1p56  =  0.5528  ==  J  vol. 

oxygen. 


LECTURE    ON    NITER    OR    SALTPETER.  183 

Hence  the  gas  is  NO*  or  N20. 

The  properties  of  the  gas  N2  0  are  remarkable.  It 
was  discovered  by  Priestly  in  1776,  and  Sir  H.  Davy 
demonstrated  its  composition.  The  gas  is  colorless, 
possesses  a  faint  sweetish  taste  and  slight  aromatic 
odor.  One  cubic  centimeter  at  0°  C.  weighs  0.001974 
gram.  The  gas  is  quite  soluble  in  cold  water.  At 
0°  C.  one  volume  water  absorbs  1.3  volumes  of  the 
gas,  but  at  20°  C.  only  0.67  volume.  A  taper  burns 
in  the  gas  more  brightly  than  in  air,  almost  as  in 
oxygen  gas.  The  gas  can  be  taken  into  the  lungs 
(breathed)  without  any  discomfort.  Quite  on  the 
contrary  ;  its  action  when  breathed,  is  that  of  a 
stimulant.  The  nerves  become  excited,  the  effect 
is  similar  to  that  of  alcohol  and  ether — intoxication 
ensues,  either  numbness  or  acute  mania.  The  effect 
is  not  by  any  means  alike  on  all  persons.  Sir  H. 
Davy  gave  it  the  name  laughing-gas,  pleasure  gas. 
Its  application  in  dentistry  is  well  known.  Dentists 
use  it  with  nervous  persons,  who  are  unwilling  to 
stand  up  against  pain.  Though  not  quite  without 
danger,  serious  after-effects  are  less  likely  through 
its  use  than  through  other  anaesthetics — ether  or 
chloroform.  The  dentists  buy  the  gas  in  the  com- 
pressed state,  in  copper  cylinders.  At  0°  C.  the  gas 
becomes  liquid  under  a  pressure  of  30  atmospheres, 
that  means  when  30  volumes  are  compressed  into 
the  space  of  one  volume,  approximately  ;  300  litres 
of  the  gas  yield  400  c.c.  of  liquid  N20.  When  this 
liquid  is  allowed  to  evaporate  it  produces  intense 
cold,  like  liquid  air,  and  part  of  it  becomes  solid  as 


184 


CHEMISTRY    SIMPLIFIED. 


snow.  The  liquid  N20  boils  at  -89°  C.,  and  be- 
comes solid  at  -100°  C.  For  use  of  the  dentists 
the  compression  of  the  gas  is  only  carried  so  far 
that  about  10  volumes  are  compressed  into  1  vol- 
ume ;  which  means  a  pressure  of  150  pounds  per 
square  inch. 

Preparation  of  the  gas  on  manufacturing  scale.  The 
salt  NH.4(N03),  ammonium  niter  or  nitrate,  breaks 
up  into  N20  and  H20  when  heated  : 

NH4./xr03)  +  heat  =  N20  +  2H20, 
and  thus  furnishes  an  excellent  raw  material.     It 


FIG.  51. 


is  not  expensive.  Apparatus  as  shown  in  Fig.  51 
will  enable  you  to  make  the  gas  quickly.  R  is  a 
small  retort,  into  which  has  been  put  the  ammonium 
nitrate  at  A.  The  stand  S  holds  the  retort.  L  is  a 


LECTURE  ON  NITER  OR  SALTPETER.     185 

Liebig  condenser  with  the  water  inflow  at  i  and  its 
outflow  at  o.  The  condensed  water  and  the  gas 
separate  in  the  flask  C,  the  gas  passes  into  the  dry- 
ing tube  D  and  issues  dry  at  G,  whence  it  may  be 
conducted  into  any  desired  holder,  or  to  a  compress- 
ing pump.  Substitute  large  iron  vessels  for  the 
small  glass  vessels  and  you  have  the  manufacturing 
plant. 

Recapitulation  of  the  oxyds  of  nitrogen  : 

N205  (contained  in  the  nitrates)  does  not  exist  in 
free  state. 

N204   (contained    in  the  very  unstable  hyponi- 
trates)  brown  fumes. 

N203  (contained  in  the  nitrites)  blue  liquid  in 
free  state. 

N202  (forms  no  salts)  originator  of  brown  fumes. 

N20  (forms  no  salts)  laughing-gas. 
Nitrogen  shows  five  different  valences,  from  inono- 
to  penta-valent,vbut  all  of  them  are  weak.  With 
other  elements  similar  tendencies  are  observed,  the 
smaller  the  affinity  between  two  elements,  the 
greater  the  number  of  combinations  into  which 
they  enter. 


CHAPTER  XL 

AMMONIA,  A  VOLATILE  ALKALI.    A  COMPLEX 
METALLIC  RADICAL. 

AMONG  other  facts  concerning  the  action  of  KOH 
and  NaOH,  we  gathered  that  these  hydroxyds  and 
their  water  solutions  can  dissolve  zinc  with  the  evo- 
lution of  hydrogen  ;  when  the  hydrogen  is  thus 
generated  we  say  it  is  in  the  nascent  state,  meaning 
by  this  word  (literally  "  being  born  ")  that  there  is  a 
special  force  or  energy  connected  with  it,  and  which 
the  gas  has  lost  after  it  is  once  set  free  and  allowed 
to  collect  or  to  dissipate.  It  is  a  play  of  the  affini- 
ties. We  observe  that  a  solution  of  indigo  is  not 
decolorized  by  shaking  it  with  hydrogen  gas.  Yet 
when  zinc,  dilute  sulfuric  acid  and  indigo  are 
brought  together,  the  liquid  becomes  colorless. 

Blue  indigo  +  Zn  +  H2S04  +  water  =  white  in-' 
digo  -}-  Zn(S04)  +  water.  Hydrogen  is  not  evolved 
until  all  the  blue  indigo  is  changed  into  white  in- 
digo, and  we  ascribe  the  change  to  nascent  hydrogen. 
Thus  also  when  niter,  NaHO,  and  zinc  act  together, 
the  escaping  gas  possesses  not  only  a  peculiar  odor, 
but  the  gas  turns  red  litmus  to  blue.  There  must 
be  with  the  hydrogen  a  new  volatile  body  which  pos- 
sesses the  properties  of  the  alkaline  hydroxyds.  Let 
this,  as  yet  suspicious,  body  be  named  ammonia. 
(186) 


AMMONIA,  A    VOLATILE    ALKALI.  187 

Passing  the  gas  into  water,  the  latter  soon  acquires 
alkaline  reaction  and  the  power  to  neutralize  acids. 
If  these  neutralized  acids  be  evaporated,  crystals 
form,  characteristic  for  each  acid,  the  same  as  if 
those  acids  had  been  neutralized  by  KOH.  Yet  if 
these  crystals  be  heated  over  an  open  flame,  they 
will  completely  disappear,  totally  differing  from  any 
of  the  metallic  salts.  The  total  volatilization  is 
proof  that  the  body,  which  here  takes  the  place  of  a 
metal,  cannot  contain  either  zinc  or  sodium,  and 
since  besides  these,  only  the  elements  X,  0,  H  had 
been  in  the  generating  solution,  they  alone  can  con- 
stitute the  new  body.  Hydrogen  we  know  to  be  a 
metal,  because  it  takes  the  place  of  a  metal  in  the 
salts,  producing  the  hydrogen  salts  or  acids.  Oxy- 
gen and  hydrogen  together  form  water,  which  can 
take  the  place  of  a  metallic  oxyd,  but  not  of  a  metal, 
hence  we  must  conclude  that  the  new  body  must 
contain  nitrogen. 

Investigation.  The  first  step  will  be  the  prepara- 
tion of  a  sufficient  supply  of  the  ammonia  gas.  A 
word  about  the  name.  We  know  that  the  name  of 
the  Egyptian  sun  god  was  Rha  Ammon;  also  that 
the  name  of  a  powerful  tribe  of  Bedouins  in  the 
desert  to  the  southeast  of  the  Dead  Sea,  in  Palestine, 
was  Beni  Ammon,  in  Hebrew,  the  sons  of  Ammon, 
as  we  would  say  the  sons  of  the  sun.  It  is  my  be- 
lief that  the  name  ammonia  is  connected  in  some 
way  with  Rha  Ammon,  though  I  cannot  say  how. 
The  Egyptian  priests  must  have  known  this  body, 
and  for  its  revivifying,  penetrating  odor  likened  it 


188 


CHEMISTRY    SIMPLIFIED. 


to  the  effect  of  the  sun's  rays.  There  is  no  histor- 
ical record  in  existence  to  substantiate  my  view. 
In  the  Latin  translation  of  Gebers  works  (ninth 
century  A.  D.)  the  name  appears  sal  armeniacum, 
which  would  mean  the  salt  of  Armenia,  but  that 
stands  also  for  rock  salt.  I  believe  it  is  a  mis- 
spelling. 

Preparation  of  ammonia.     Put  into  a  500  c.c.  flask 
(Fig.  52)  25  grams  of  NaOH,  or  about  that  much, 

FIG.  52. 


75  c.c.  of  water,  20  grams  of  zinc  (in  turnings),  a 
piece  of  bright  sheet-iron,  and  5  grams  of  niter. 
Stopper  the  flask  and  connect  by  rubber  tubing 
with  a  Will's  condenser.  The  flask  should  stand 
on  a  tripod  upon  wire  gauze.  Heat  gently  and  keep 
up  a  slow  evolution  of  gas.  The  condenser  is 
charged  with  20  c.c.  of  water  and  5  c.c.  of  HC1  con- 
centrated. It  is  best  to  place  a  tube,  T,  between 
flask  and  condenser  to  receive  any  liquid  spatter- 
ings.  Will's  condenser  is  especially  adapted,  be- 


AMMONIA,  A    VOLATILE    ALKALI.  189 

cause  either  of  the  bulbs,  a,  6,  can  hold  more  than 
the  volume  of  liquid  indicated,  hence  no  danger  of 
the  running  back  of  the  liquid  into  T  should  a 
vacuum  occur  in  F,  nor  a  running  out  at  C  should 
the  escape  of  gas  become  tumultuous  at  any  time. 
The  addition  of  some  litmus  to  the  liquid  in  W  is 
advisable ;  so  long  as  the  color  remains  red  we  know 
that  the  liquid  is  still  able  to  take  up  more  ammo- 
nia. Any  hydrogen  mixed  with  the  ammonia  will 
escape  at  the  point,  C,  of  the  condenser.  The  action 
must  not  be  overhurried.  In  hurrying  much  more 
hydrogen  escapes,  doing  no  work.  As  soon  as  all 
the  air  is  displaced  from  F,  T,  and  W,  you  will  note 
a  tendency  of  the  liquid  in  W  to  advance  against 
the  gas,  to  pass  up  into  the  bulb,  a,  an  action  which 
indicates  the  strong  affinity  between  ammonia  and 
HC1.  It  will  take  several  hours  to  accomplish  the 
complete  change  of  the  niter  into  ammonia.  To- 
wards the  end  it  will  be  well  to  set  T  into  a  glass 
containing  boiling  water  to  drive  out  the  ammonia 
from  the  liquid  which  may  have  been  condensed  in 
T.  Then  empty  liquid  from  W  into  an  evaporating 
dish,  and  evaporate  over  a  water-bath.  A  white, 
granular  residue  will  be  obtained  composed  of  cubic 
crystals  like  those  of  common  salt,  NaCl  or  KC1, 
which  is  another  indication  that  ammonia  must  be 
a  body  similar  to  Na  and  K.  We  will  name  this 
white  salt  ammonium  chlorid  =  Am.Cl.  In  the 
drug  trade  it  is  named  sal  ammoniac.  Bringing  this 
salt  together  with  Na(OH)  or  K(OH)  or  Ca(HO)2  we 
observe  at  once  a  pungent  odor  of  ammonia. 


190 


CHEMISTRY    SIMPLIFIED. 


K(OH)  +  Ara.Cl  =  KC1  +  H20  +  Ammonia. 
It  follows  from  this  action  that  there  must  be  con- 
tained in  the  salt  one  hydrogen  besides  the  ammonia. 
Important  observation  to  be  remembered.     Of  the 
three  hydroxyds  the  one  best  servicable  for  making 
ammonia   is   Ca(HO)2.      Why?      Because   it  is  a 
powder.     Even  better  is  the  oxyd  CaO,  because  if 
an  excess  of  it  be  added,  then  this  excess  will  retain 
the  water  in  the  form  of  Ca(HO)2.     Even  by  rub- 
bing together  Am.Cl  and  CaO,  ammonia  is  set  free. 
The  process  follows  along  the  equation 
2Am.Cl+2CaO=CaCl2+2  Ammonia+CaO.(H20) 
Pure  dry  ammonia  gas  results. 

COMPOSITION  OF  AMMONIA. 

Let  the  generating  apparatus  be  set  up  as  shown 
FIG.  53. 


in  Fig.  53.     In  the  small  flask  (not  more  than  100 
c.c.)  put  the  mixture  !/(4CaO+lAmCl)  so  that  the 


AMMONIA,  A    VOLATILE    ALKALI.  191 

bulb  is  nearly  full.  To  insure  perfect  dryness  of 
the  gas,  let  it  pass  through  two  U-tubes  U  and  U 
both  filled  with  pieces  of  burnt  linie,  pea  size. 

Proof  that  ammonia  contains  hydrogen.  Rig"  a 
hard  glass  tube  T,  \ff  diameter,  12"  long,  as  shown 
in  Fig.  54.  Between  two  asbestus  plugs  b  and  br 
fill  in  coarse  copper  oxyd  and  ignite  both  asbestus 
and  oxyd  thoroughly,  before  filling  the  tube.  Let 
the  plugs  be  3  to  4  inches  apart.  Arrange  shield  S  so 
that  only  the  filled  part  becomes  heated,  the  empty 


FIG.  54. 

S 

n 

= 

B 

k 

V^ 

fell  r  "  I.  ^ 

/'U 

JL__mj_  ^     ^ 

4    IT      I          1      V 

part  projecting  beyond  the  shield.  Fill  the  tube 
with  ammonia  gas  by  attaching  t  to  P  in  Fig.  53. 
Then  heat  a  to  redness,  and  let  the  gas  pass  slowly 
(by  heating  generating  bulb  very  gently).  Soon  we 
see  moisture  appear  in  the  cool  tube  at  TF.  Mean- 
while connect  the  outlet  of  T  by  means  of  a  bent 
tube  with  the  test-tube  B,  which  stands  inverted  in 
basin  Cboth  filled  with  dilute  H2(S04).  Whatever 
gas  collects  in  B  must  be  nitrogen  (prove  by  its 
negative  actions),  because  any  ammonia  gas  passing 
out  undecomposed  will  become  absorbed  by  the 
dilute  acid.  That  the  condensed  moisture  at  TF  is 
water  we  prove  by  bringing  together  with  it  a  small 
piece  of  potassium.  But  water  could  form  only  if 
the  ammonia  contained  hydrogen. 


192 


CHEMISTRY    SIMPLIFIED. 


Proof  that  ammonia  contains  no  oxygen.  We  re- 
place the  copper  oxyd  at.  a,  Fig.  54,  by  a  bright 
copper  wire,  or  a  strip  of  bright  copper  foil  and 
repeat  the  experiment  at  red  heat.  The  copper  does 
not  cover  itself  with  a  film  of  oxyd.  This  is  proof  of 
the  absence  of  oxygen. 

Hence  ammonia  must  be 


Demonstration  that  the  ratio.  — '  =  -.     Let  a  small 

p       3 

volume  of  the   pure  ammonia   gas  pass  into  the 
eudiometer  E,  Fig.  55,  over  perfectly  dry  mercury. 


FIG.  55. 


FIG.  56. 


/     ~ 


; 


m 


Dry  the  eudiometer,  inside  and  outside,  most  thor- 
oughly, before  filling  in  the  dry  mercury.  A 
eudiometer  is  a  glass  tube  open  at  one  end,  made 
of  strong  glass,  either  graduated  or  not  graduated, 
but  having  two  thin  platinum  wires  fused  into  the 
glass  near  the  closed,  or  upper,  end  -  -  +,  so  that  an 
electric  current  of  high  potential  may  be  sent  across 
in  form  of  a  spark.  Let  m  designate  the  portion  of 


AMMONIA,    A    VOLATILE    ALKALI.  193 

the  mercury  meniscus  after  the  ammonia  gas  has 
entered.  Then  turn  on  the  current  which  has  been 
transformed  to  high  potential  by  means  of  a  Rhum- 
korf  coil.  We  notice  at  once  an  increase  in  the 
gas  volume ;  rapid  increase  at  first,  but  slowing 
down  by  geometric  progression  until  the  maximum 
enlargement  of  the  volume  has  been  reached  at  2m 
as  shown  in  Fig.  56.  The  volume  has  doubled  ; 
the  hydrogen  and  nitrogen  are  now  merely  mixed  to- 
gether, the  energy  of  the  shocks  from  the  sparks  hav- 
ing broken  the  chemical  bond.  Now  let  us  assume 
that  the  entire  volume  of  the  gas  be  hydrogen,  i.  e., 
2  vols.,  let  one  vol.  of  pure  oxygen  be  added,  mak- 
ing altogether  3  vols.  of  gas.  Let  the  spark  pass 
between  the  wires  (under  proper  precautions,  that  is 
covering  the  mercury  trough  with  a  towel  and  hold- 
ing down  eudiometer  with  the  left  hand).  Had  our 
assumption  been  correct  there  would  now  only  be 
contained  in  tube  aqueous  vapor  and  liquid  water. 
We  must  remove  this  water,  because  we  started 
with  dry  gas,  by  bringing  into  the  gas  a  ball  of 
K(OH)  fused  to  a  thin,  soft  wire.  KOH  absorbs 
water  eagerly.  A  ball  of  fused  CaCl2  will  answer 
also.  We  watch  the  gas  from  time  to  time  and 
remove  the  drying  ball  when  the  volume  remains 
constant  for  a  full  hour.  Since  we  know  that 
nitrogen  will  certainly  be  in  the  residue,  we  must 
have  a  certain  and  unknown  excess  of  oxygen  after 
the  explosion,  for  we  put  oxygen  equal  to  J  of  the 
total  gas  H  -f-  N.  Let  this  excess  of  oxygen  =  dO, 
then  the  residue  will  be  =  N  -f-  dO.  Suppose  we 
13 


194  CHEMISTRY  SIMPLIFIED. 

started  with  one  vol.  ammonia  gas  =  10  c.c.  By 
decomposition  this  became  =  20  c.c.  By  addition 
of  one  vol.  of  oxygen  =  10  c.c.  this  became  =  30  c.c. 
Now  we  explode  the  mixture  and  remove  aqueous 
vapor,  and  find  that  30  c.c.  have  shrunk  to  7.5  c.c. 
Then  30  —  7.5  c.c.  =  22.5  c.c.  here  disappeared  in 
form  of  H20  ;  f  of  this  contraction  was  hydrogen,  J 
oxygen. 


22  5 

~-  =  7.5  c.c.  of  0 

But  we  had  used  10  c.c.  of  0,  hence  d  0  =  10  — 
7.5  =  2.5;  hence  N  +  d  0  =  N  +  2.5  =  7.5  (gas 
volume  after  explosion);  N  =  7.5  —  2.5  =  5  c.c.; 
hence  ratio  ~  =  •£§•  =  J.  The  formula  of  ammonia 
is  NH3.  Into  10  c.c.  of  H3N  are  compressed  15  c.c. 
H  +  5  'c.c.  N.  Into  1  c.c.  of  H3N  are  compressed 
1.5  H  +  0.5  N,  or  two  volumes  are  condensed  into 
one. 

1£  vols.  hydrogen  weigh  gram  .     .     .     0.1038 
\  vol.  nitrogen  weighs  gram      .     .     .     0.4856 

0.5894 

which  is  the  calculated  specific  gravity  or  volume 
weight  of  ammonia,  and  agreesjairly  well  with  the 
experimental  specific  gravity  of  0.596.  The  mole- 
cular weight  (H  =  1)  is  14  +  3  =  17. 

The  chemical  nature  of  ammonia  —  ammonium. 
Ammonia  gas  is  easily  absorbed  by  water.  1  c.c. 
of  water  at  0°  C.  will  absorb  1050  c.c.  of  the  gas; 


AMMONIA,  A    VOLATILE    ALKALI.  195 

much  heat  is  produced  by  the  absorption.  The  re- 
sulting liquid,  be  it  concentrated  or  dilute,  has  the 
same  pungent  odor  as  the  gas.  The  liquid  possesses 
the  biting  taste  of  potassium  and  sodium  hydrates. 
Raises  a  blister  on  the  tongue  or  lips.  The  liquid 
is  lighter  than  water  ;  at  +  14°  C.  its  specific  gravity 
is  0.8844,  and  contains  35.0  per  cent,  of  NH3.  This 
liquid  goes  in  the  drug  trade  by  the  name  aqua  am- 
monia or  ammonia  water.  We  chemists  call  it  ammo- 
nium hydrate.  Because  from  the  actions  of  this 
liquid  towards  the  acids,  we  conclude  that  as  soon 
as  the  gas,  NH3,  comes  together  with  water  it  com- 
bines with  the  latter,  thus 

NH3  +  H20=(NH4XHO)=aram<mmra  hydroxyd. 

One  hydrogen  leaves  IPO,  and  attaching  itself  to 
NB  3  brings  forth  the  metallic  radical  (NH4).  Here- 
tofore we  have  only  had  non-metallic  complex  rad- 
icals, such  as  (SO4),  (NO3).  This  radical,  (NH4), 
we  name  ammonium.  Note  carefully  the  difference 
in  the  words  ammonia  and  ammonium,  and  try  not 
to  confound  them  in  your  speech.  Ammonia  is  the 
real,  actual  compound,  NH3;  ammonium  the  hypo- 
thetical metal,  NH4.  I  say  hypothetical  because 
we  have  no  means  at  present  to  isolate  it ;  in  at- 
tempting to  tear  (NH4)  from  (HO)  we  always  get 
NH3  -j-  H20  =  ammonia  -f-  water.  And  yet  there 
is  no  unproven  assumption  in  chemistry  more  cer- 
tain than  this,  that  ammonium  would  show  all  the 
physical  characters  of  a  metal  if  we  could  separate 
and  condense  it,  even  as  hydrogen  itself  would  do. 


196 


CHEMISTRY    SIMPLIFIED. 


Indirect  or  circumstantial  proof  of  the  ammonium 
theory.  Let  us  introduce  (Fig.  57)  into  the  tube,  T, 
over  mercury,  one  volume  of  dry  HC1  and  one  vol- 
ume of  dry  NH3.  The  one  gas  is  strongly  acid,  the 
other  strongly  alkaline.  In  order  to  get  the  vol- 
umes equal  let  t  be  a  small  tube  holding  10  c.c.  up 
to  the  mark  m.  If  t  be  filled  with  mercury  and 
then  held  so  that  the  upper  rim  of  the  sticker  falls 
together  with  the  level  of  the  mercury  in  the  trough, 


V,  and  if  now  the  gas-delivery  tube  be  brought 
under  the  rim  and  the  gas  allowed  to  enter  until  all 
the  mercury  is  displaced,  that  is,  until  the  bubbles 
come  up  on  the  outside,  and  if  we  do  the  same  with 
the  other  gas,  then  we  have  measured  the  gases 
exactly  at  the  same  pressure  and  temperature.  For 
the  transmission  of  the  gas  from  t  into  T  we  incline 
Tas  much  as  possible,  and  then  with  the  left  hand  t  is 
inclined  in  the  opposite  direction,  the  open  end  of  t 
shoved  under  the  open  end  of  1 ;  the  closed  end  of 
t  is  then  pressed  down,  and  the  entire  volume  of  gas 


AMMONIA,  A    VOLATILE    ALKALI.  197 

passes  above  the  mercury  into  T.  When  the  two 
gases  meet  a  white  cloud  forms ;  the  mercury  rises 
and  occupies  practically  the  whole  of  T.  Both  gases 
have  disappeared,  no  hydrogen  has  been  liberated, 
we  have 

HC1  +  NH3  =  HCLNH3,  (sal  ammoniac.) 
But  the  resulting  body  is  a  white  salt  crystallized  in 
cubes  and  octahedrons,  or  a  combination  of  the  two* 
exactly  the  same  as  KC1  and  NaCl.  By  action  of 
H2S04  upon  this  salt  we  obtain  HC1,  as  we  did 
from  NaCl  and  KCL  Hence  we  deduce  that  a  body 
must  be  in  the  salt,  in  every  respect  equal  to  either 
sodium  or  potassium.  That  is  ammonium,  NH4. 

HCLNH3  =  (NH4).C1  =  AmCl. 
Some  chemists  always  write  Am.  instead  of  (NH4) 
in  order  to  lay  stress  upon  the  metallic  nature  of 
the  group  (NH4).     Because  one  volume  HC1  com- 
bines with  one  volume  NH3  we  say  ammonium  is 
a  monad,  a  monovalent  radical ;  hence  there  is 
one  nitrate       (NH4).(N03) 

twosulfates  /  (NH4).H.(S04)  acid  sulfate,  bisulfate 

3  I  (NH4)2.(S04)  neutral  sulfate 
one  chlorid      (NH4).C1. 

Knowing  now  the  composition  and  nature  of  ammo- 
nia and  ammonium,  we  can  write  the  equation  of 
its  formation  from  Na(OH),  Zn,  Na(N03),  or  K(N03) 
thus,  in  two  stages, 

(1)  2Na(OH)  +  Zn  =  Na2Zn02  +  2H 

(-2)  2Na(N03)  +  16H  =  Na20  +  5H20  +  2NH3 


198  CHEMISTRY    SIMPLIFIED. 

or  16Na(OH)+8Zn+2Na(N03)  +  water  = 

8Na2Zn02  +  4H20  +  2Na(OH) 

or  8Na(OH)  +  4Zn  -f  Na(N03)  -f  water  =  NH3  + 

4Na2Zn02  -f  Na(OH)  +  2H20. 

The  incentive  for  the  action  is  the  tendency  of  the 
zinc  and  sodium  to  form  the  salt  Na2Zn02  (sodium 
zincate),  then  the  hydrogen  in  the  nascent  state  attacks 
the  niter,  substitutes  itself  for  the  oxygen  and 
changes  the  latter  into  H20.  A  very  similar  ac- 
tion takes  place  when  zinc  is  in  presence  of  dilute 
H2S04  and  H(N03).  Here  the  incentive  lies  in  the 
tendency  of  zinc  to  displace  the  hydrogen  in  H2S04 
and  to  form  Zn(S04).  Then  the  nascent  hydrogen 
will  attack  HNO3  as  in  the  alkaline  solution.  Thus  : 

9H2S04  +  8Zn  -f  2HN03  +  much  water  = 

SZnSO4  +  (NH3)2H2S04  -f  6H20. 
It  also  follows  that  a  similar  action  will  take  place 
when  zinc  acts  upon  a  very  dilute  water-solution  of 
H(N03)   itself,    but  in  this  case  only  part  of  the 
nitrogen  becomes  changed  into  NH3. 
Thus  10H.(N03)  +  4Zn  +  water  =  4Zn(N03)2  + 

NH3.HN03  +  3H20. 

Of  9  molecules  H(N03)  only  one  becomes  changed 
into  NH3.  The  student  must  practice  on  these 
equations  specially,  because  on  them  depends  a 
method,  and  a  very  good  one  it  is,  to  determine  in 
an  unknown  substance  the  percentage  of  nitrate  and 
nitrite.  For  it  is  evident  that  the  action  must  be 
similar  upon  nitrites  ;  one  molecule  of  nitrite  re- 
cjuires  2H  less  for  its  conversion  into  NH3,  Besides 


AMMONIA,  A    VOLATILE    ALKALI.  199 

these,  which  we  may  designate  as  inorganic  or 
mineral  processes,  there  are  many  other  processes  by 
which  ammonia  is  generated,  namely  the  processes 
of  fermentation  and  putrefaction  ;  the  latter  process  is 
only  a  variety  of  fermentation  and  often  referred  to 
as  putrid,  or  stinking,  fermentation.  1.  Ammonia 
forms  in  the  curing  of  tobacco.  The  air-dry  leaves 
being  made  into  piles,  soon  begin  to  feel  warm 
and  give  out  a  strong  odor  of  ammonia.  The 
nicotin  of  the  leaf  which  contains  much  nitrogen  is 
broken  up  by  the  ferment  (a  fungus)  and  the  tobacco 
looses  its  rankness.  The  chemical  reactions  are 
complex  and  could  not  be  understood  by  you  at 
your  present  state  of  knowledge.  2.  Ammonia 
forms  in  the  fermentation  of  urine,  because  this  se- 
cretion contains  much  urea — a  highly  nitrogenous 
substance  like  nicotine.  3.  Ammonia  forms  in  the 
distillation  of  soft  coal ;  because  the  coal  contains 
from  one  to  two  per  cent,  of  nitrogen  ;  and  although 
one  can  only  get — say  20  Ibs.  at  most — of  ammonium 
sulfate,  by  bringing  the  gases  from  the  distillation 
in  contact  with  H2S04,  yet  so  many  millions  of  tons 
of  coal  are  distilled  every  year,  that  the  total  ofj 
ammonium  sulfate  is  enormous,  and  constitutes  inf 
fact  the  only  commercially  important  source  of  supply/ 
of  ammonia.  The  great  bulk  of  this  goes  back  to 
the  field  as  fertilizer,  to  supply  the  growing  crops 
with  nitrogen.  Much  is  however  consumed  chemi- 
cally in  the  arts  and  manufactures.  Though  not 
immediately  a  subject  for  the  miner  or  metallurgist, 
yet  every  engineer  ought  to  be  acquainted  with  these 
sjaort  statements. 


200 


CHEMISTRY    SIMPLIFIED. 


Ammonia  combines  with  many  bodies,  among 
others  with  silver  chlorid  and  calcium  chlorid. 
Note  this,  so  that  you  do  not  attempt  to  dry  the  gas 
by  passing  through  CaCl2.  On  the  other  hand,  we 
may  utilize  this  fact  to  procure  liquid  NHS  (not 
ammonia  water).  AgCl  is  better  suited  than  CaCl2. 
Bring  the  dried,  pulverized  AgCl  into  a  tube  and 
pass  over  it,  slowly,  dry  NH3  so  long  as  the  latter 
is  absorbed.  Then  bend  a  strong  glass  tube  Finto 
a  knee  Fig.  58,  and  pour  the  AgCl.NH3  into  this 
tube.  Clean  the  tube  at  d  and  draw  it  out  over  the 
lamp,  making  a  good  strong  job.  The  tube  will  be 
then  as  shown  at  a  in  Fig.  58.  The  AgCl.NH3  lies  at 

FIG.  58. 


S.  Immerse  the  pointed  end  into  snow  or  ice  and 
heat  S  slowly.  Soon  a  colorless,  very  mobile  liquid 
will  condense  at  L;  this  is  liquid  NH3.  The 
liquefaction  is,  in  this  case,  produced  by  the  self- 
pressure  of  the  gas  as  it  becomes  expelled  at  S.  If 
allowed  to  stand  the  liquid  will  disappear  because 
the  AgCl  has  once  again  taken  up  NH3.  The  ex- 
periment may  be  repeated  over  and  over.  At  — 40° 
C.  the  gas  becomes  liquid  without  any  extra  pres- 
sure. At  — 90°  C,  the  liquid  turns  into  a  snow- 


AMMONIA,  A    VOLATILE    ALKALI. 


201 


white  solid,  which  melts  at  — 75°  C.  and  has  no  odor, 
owing  to  the  absence  of  tension  at  this  low  tempera- 
ture. The  tension  of  liquid  NH3  at  0°  C.  is  7 
atmospheres,  and  its  specific  gravity  =  0.63  (water 

In  the  chemical  factories  aqua  ammonia  or  am- 
monium hydrate  is  prepared  from  (NH4)2S04  by 
means  of  milk  of  lime  in  large  iron  cylinders  C, 
Fig.  59. 

(NH4)2S04  +  Ca(HO)2  +  water+heat  =  2NH3-f 
Ca(S04)  +  2H20  +  water.  It  is  necessary  to  keep 


the  mixture  in  constant  motion  by  means  of  a 
stirring  wheel  W,  the  shaft  of  which  passes  through 
well  tightened  stuffing  boxes  B  E' .  The  manhole 
M  serves  to  introduce  materials ;  the  live  steam 
enters  at  8;  the  ammonia  gas  together  with  a  cer- 
tain quantity  of  water  vapor  passed  out  at  A.  0  is 
the  discharge  opening,  and  the  pulley  P  transmits 
the  power  to  the  wheel  W,  From  A  the  gas  passes 


202  CHEMISTRY    SIMPLIFIED. 

through  a  cooler  in  which  the  aqueous  vapor  also 
condenses  and  flows  partly  as  gas,  partly  as  highly 
concentrated  liquid  into  glass  balloons  (carboys),  or 
iron  cylinders  if  the  liquid  is  to  be  shipped  into  hot 
climates.  The  carboys  must  be  most  carefully 
packed  in  straw  or  salt  hay,  for  if  a  carboy  should 
break,  the  hold  of  a  ship — for  instance — could  not 
be  entered  ;  the  gas  is  deadly,  causing  immediate 
suffocation. 

The  concentrated  aqua  ammonia  is  much  used  in 
the  Carre  ice  machine,  the  construction  of  which  is 
explained  in  physics.  Its  principle  is  that  a  con- 
centrated solution  of  ammonia  gives  out  J  its  NH,S 
as  gas,  without  any  water,  when  gently  heated.1  If 
the  gas  be  taken  by  a  suitable  pump  and  forcpd 
into  a  strong  tube,  which  is  cooled  by  running 
water,  so  as  to  remove  the  heat  of  compression,  and 
if  the  compressed  gas  be  allowed  to  flow  into  an- 
other tube  which  is  surrounded  by  water — stagnant 
—then  this  water  will  fall  below  its  freezing-point, 
it  will  become  ice.  Why?  Because  the  compressed 
gas  in  expanding  into  the  tube  (from  which  the  air 
has  been  pumped)  will  absorb  the  heat  necessary 
for  its  expansion  from  the  surrounding  objects. 
Theoretically  no  ammonia  is  lost,  because  the  ex- 
panded gas  is  again  taken  hold  of  by  the  pump  and 
compressed  as  before.  Practically  a  certain  portion 
is  lost  through  unavoidable  leakage  of  the  appara- 
tus, and  must  be  replenished. 

The  aqua  ammonia  also  serves  as  raw  material 
for  the  preparation  or  manufacture  of  the  other 


AMMONIA,  A    VOLATILE    ALKALI.  203 

salts,  the  nitrate  (for  the  manufacture  of  laughing 
gas),  the  chlorid  (sal  ammoniac),  the  carbonate  and 
the  bicarbonate.  The  latter  salts  are  also  known  as 
hartshorn  salt,  because  they  were  formerly  obtained 
by  distilling  hartsliorn  or  other  kinds  of  horn.  It 
has  been  mentioned  that  horn  and  skin  as  well  as 
hair  are  so-called  albumenoid  bodies  (like  albumen 
— white  of  egg)  containing  from  15  per  cent,  to  17 
per  cent,  of  nitrogen.  Now  if  the  horn  be  heated 
in  a  closed  vessel,  it  will  char  and  give  off  fumes  as 
well  as  gases.  Amongst  these  is  the  ammonium  car- 
bonate, and  it  may  be  condensed. 

Both  carbonate  and  bicarbonate  evaporate  in  the 
air,  giving  a  strong  odor  of  ammonia,  hence  known 
as  volatile  salt,  smelling  salts,  to  be  applied  to  fainting 
persons.  Owing  to  their  easy  and  complete  volatili- 
zation, these  salts  are  used  instead  of  baking  soda 
in  the  making  of  fine  cake.  Being  incorporated 
into  the  dough  (flour,  milk,  sugar,  eggs),  the  salt 
becomes  gas  in  the  oven,  raises  the  dough,  and 
leaves  neither  taste  nor  smell. 

(NH4)2C03  =  normal  or  neutral  carbonate. 

H20.(NH4)2C03.C02  =  bicarbonate. 
The  neutral  (NH4)2C03  is  a  highly  unstable  salt. 
As  soon  as  heat  is  applied  it  breaks  up.     The  trans- 
parent or  translucent  crusts  which  we  buy  as  neu- 
tral carbonate  have  normally  the  composition  : 

2((NH4)2C03).H2C03  =  sesquicarbonate,  or  1J 
carbonate. 

The  salt  is  made  by  heating  together  in  an  iron 
retort  ; 


204 


CHEMISTRY    SIMPLIFIED. 


(NH4)2S04+CaC03  (chalk)  or  (NH4)Cl+CaC03. 
Th.e  bicarbonate  is  usually  a  granular  substance, 
but  may  easily  be  obtained  in  long  prismatic,  ortho- 
rhombic  crystals,  white  or  colorless.  Composition 
as  above,  (NH4)2.C03.H2C03. 

It  is  prepared  by  passing  lime-gas  into  a  saturated 
solution  of  the  sesquicarbonate.  Being  less  soluble 
than  the  latter  salt,  the  bicarbonate  falls  out  in 
grains. 

Sal  ammoniac,  ammonium,  chlorid,  (NH4).C1.  A 
white  or  colorless  salt.  Sometimes  a  loose,  fluffy 

FIG.  60. 


powder  composed  of  small  cubic  crystals.  Mostly 
in  lumpy  crusts,  dense,  as  if  they  had  been  melted, 
and  exceedingly  fibrous,  tough ;  will  not  grind  into 
powder.  To  study  the  formation  of  this  body,  place 
two  watch  glasses  alongside  of  each  other,  pour  into 
the  one  concentrated  HC1,  into  the  other  concen- 
trated aqua  ammonia,  and  cover  the  two  with  an 


AMMONIA,  A    VOLATILE    ALKALI.  205 

inverted  beaker  glass  or  bell  jar.  Both  liquids  giv- 
ing out  gas,  there  will  be  at  once  a  white  cloud. 
The  glass  and  table  cover  themselves  with  snowy 
sal  ammoniac,  feathered  and  fern-like  aggregates  of 
small  crystals.  At  the  point  of  sublimation  or  vol- 
atilization the  salt  breaks  up  into  HC1  +  NH3.  One 
smells  both  at  the  same  time,  but  so  soon  as  the 
temperature  drops  reunion  ensues,  hence  the  salt 
can  be  sublimated  in  earthenware  vessels,  glazed,  to 
avoid  yellow  stains.  In  Fig.  60,  a  is  earthenware, 
b  is  earthenware,  c  is  a  cast-iron  vessel  into  which  the 
vessel,  a,  fits,  M  is  the  crude  salt,  and  S  represents 
the  sublimated  crusts  of  the  salt. 

Use  of  sal  ammoniac  in  soldering.  Soldering  means 
the  joining  together  of  two  metal  surfaces  by  means 
of  a  film  of  liquid  metal  (solder)  whose  melting- 
point  is  much  lower  than  the  melting-point  of  the 
metals  which  are  to  be  joined.  Solder  is  either 
hard  or  soft.  Hard  solder  is  an  alloy  of  2  pts.  lead 
and  1  pt.  tin  ;  soft  solder  contains  one  lead,  one  tin. 
The  soldering-hammer  or  iron  is  a  pointed  piece  of 
copper,  the  point  of  which  is  coated  with  tin.  Tin 
will  not  stick  to  heated  copper,  because  the  latter 
covers  itself  with  a  film  of  oxyd,  as  you  well  know. 
But  if  the  hot  copper  be  rubbed  together  with  the 
tin  and  sal  ammoniac,  then  the  two  metals  will  cling 
together;  the  tin  fairly  jumps  at  the  copper.  Why? 
Because  we  have  seen  that  the  (NH4).C1  when 
heated  breaks  up  into  HC1  +  NH3.  But  HC1  at 
once  converts  the  oxyd  film  into  fusible  chlorids, 
Cu2Cl2  ;  the  metals  become  bright  and  join.  After 


206  CHEMISTRY    SIMPLIFIED. 

the  hammer  is  well  tinned  it  will  hold  liquid  solder. 
And  if  now  (NH4)C1  in  powder  be  strewn  over  the 
surfaces  which  are  to  be  joined  (brass  for  instance) 
the  (NH4)C1  will  cleanse  them,  the  solder  will  ad- 
here. Liquid  HC1  or  hydrochloric  acid  may  be 
used,  but  is  inconvenient  and  not  so  effective,  be- 
cause it  evaporates  too  rapidly.  Sal  ammoniac  is 
used  in  medicine,  and  also  for  freezing  mixtures, 
because  its  solution  in  water  absorbs  much  heat. 

SOLVAY    PROCESS. 

The  Solvay  process,  also  known  as  the  ammonia- 
soda  process,  has  become  of  such  great  importance 
that  we  must  know  something  about  it.  Nearly 
one-half  of  the  world's  supply  of  soda-ash  is  now 
manufactured  by  this  method.  Like  many  other 
processes,  the  reactions  underlying  it  were  known 
many  years  before  the  mechanical  difficulties  of 
applying  them  could  be  overcome.  The  reactions 
involved  here  are 

NH3  +  H20  +  CO2  =  NH4HCO3. 

NaCl  +  NH4HC03  ==  NaHCO3  +  NH4C1. 

2NaHC03  +  heat  =  Na*CO*  +  H20  +  CO2. 

CaCO3  +  heat  =  CaO  +  CO2. 

2NH4C1  +  CaO  =  CaCl2  +  2NH3  +  H20. 

The  last  two  equations  show  the  uses  made  of  by- 
products, which  help  to  make  the  process  a  com- 
mercial success. 

The  equations  represent  the  following  operations  : 
1.  The  formation  of  NH4HC03,  which  immediately 


AMMONIA,    A    VOLATILE    ALKALI.  207 

reacts  with  NaCl,  producing  the  most  insoluble 
combination  possible,  when  CO2  is  passed  into 
purified  arnmoniacal  brine.  2.  The  calcination  of 
the  NaHCO3  to  form  the  normal  carbonate, 
Na2C03.  3.  The  decomposition  of  limestone  in  a 
lime  kiln  to  produce  CaO  for  by-product  recovery, 
and  CO2  for  operation  1.  4.  The  recovery  of  am- 
monia to  be  used  over  again. 

The  initial  supply  of  NH3  is  obtained  from  com- 
pounds that  are  the  by-products  of  the  coal-gas 
works.  Ammonium  sulphate  is  the  principle  com- 
pound used.  From  the  equations  one  might  think 
that  only  the  initial  supply  of  NH3  would  be  needed 
for  continuous  operation  ;  but  leakages  have  to  be 
made  up  from  an  outside  source. 

The  CO2  is  obtained  from  the  lime  kilns  and  also 
from  the  calcination  of  the  bicarbonate,  NaHCO3. 
The  lime-kiln  gases  are  produced  in  continuous 
kilns,  and  are  cooled  and  purified  before  being 
passed  to  the  carbon ating  towers.  These  gases  con- 
tain about  35  per  cent,  of  CO2. 

The  purified  brine  is  first  saturated  with  NH3, 
the  heat  produced  being  taken  up  by  cooling  coils 
in  the  tank.  The  ammoniacal  brine  is  then 
pumped  into  towers,  supplied  with  perforated 
diaphragms  to  make  good  contact  between  the 
liquid  and  the  CO2  which  is  forced  in  under  pres- 
sure. 

The  milky  liquid  drawn  out  from  the  bottom  of 
the  towers  contains  the  NaHCO3  in  suspension. 
This  is  separated  and  washed  by  means  of  centri- 
fugal machines. 


208  CHEMISTRY   SIMPLIFIED. 

The  bicarbonate  is  then  calcined  in  covered  cast- 
iron  ovens  to  produce  the  Na2C03,  soda-ash.  The 
gaseous  products  are  cooled  and  sent  back  to  be 
used  again.  The  soda-ash  produced  by  this  process 
is  more  fluffy  than  the  Leblanc  soda-ash,  hence  it  is 
often  recalcined  to  increase  its  density.  Ordinarily 
the  Solvay  soda-ash  is  exceptionally  pure. 


CHAPTER  XII. 
ORIGIN  AND  OCCURRENCE  OF  NITER. 

ALL  nitrates  being  easily  soluble  in  water,  we  can 
expect  to  find  any  of  them  as  mineral  only  under 
exceptional  conditions  :  that  is;  in  places  protected 
against  water.  Such  conditions  exist  in  the  rain- 
less parts  of  North  America  and  South  America, 
Asia,  and  Africa.  Europe  has  no  rainless  districts. 
But  the  Continent  of  Australia  might  yet  prove  to 
be  a  storehouse  of  niter ;  it  is  hardly  explored  as 
yet.  Nitrates  or  any  nitrogen  compounds  have 
never  yet  been  found  among  the  rock^forming 
minerals.  Thus  we  are  forced  to  the  conclusion 
that  the  air  contains  the  entire  supply  of  nitrogen 
from  which  plants  draw  this  element ;  store  it 
in  their  structure  first  as  protoplasm,  then  by  dif- 
ferentiation into  more  complex  tissues  and  com- 
binations as  the  gluten  of  the  cereal  seeds,  as  nicotine 
in  tobacco,  as  morphine  in  the  poppies  and  multitudes 
of  others.  The  animals  feed  upon  the  plants,  build- 
ing up  still  more  complex  tissues,  such  as  muscles, 
nerves,  skin,  hair.  These  in  their  turn  become 
metamorphosed,  changed  into  matters  rejected  or 
excreted.  Where  animals  congregate  in  numbers, 
as  in  cattle-yards,  stables,  etc.,  one  notices  the  soil 
reeking  with  ammonia  and  ammonium  carbonate 
14  (209) 


210  CHEMISTRY    SIMPLIFIED. 

from  the  fermentation  of  the  excreta.  Before  long 
a  white  film  appears  upon  the  surface  (when  dry 
weather  sets  in):  the  white  film  is  made  up  of  small 
prismatic  crystals  of  niter.  Hence  we  conclude  that 
ammonia  and  ammonium  carbonate  become  oxy- 
dized  in  the  presence  of  a  sufficiency  of  an  alkaline 
body — become  nitrates.  If  the  niter  film  be  scraped 
off  from  time  to  time,  the  raw  material  for  the 
manufacture  of  niter  is  given  in  these  scrapings.  It 
will  only  be  necessary  to  extract  this  niter  earth 
with  water,  strain  the  liquid  through  cotton  or  linen 
cloth,  and  evaporate  to  the  point  of  crystallization 
and  let  cool,  when  the  nitrate  will  form  in  large 
crystals,  mostly  colored  yellow  and  known  as  crude 
niter.  By  resolution  and  crystallization,  at  the  last, 
pure  niter  results.  Through  this  method  fully  one- 
third  of  the  niter  of  commerce  is  still  at  this  time 
made  in  India,  notably  in  the  valley  of  the  Ganges 
in  the  Kingdom  of  Bengal.  By  piling  up  soil  rich 
in  humus  into  heaps  or  walls,  3  to  4  feet  deep  and 
6  feet  high,  and  covering  these  heaps  with  a  shed,  a 
so-called  niter  plantation  can  be  built.  A  system  of 
gutters  or  pipes  distributes  the  liquid  animal  excre- 
tion— urine — over  the  tops  of  the  heaps,  wood  ashes 
are  strewn  over  from  time  to  time  (to  supply  the 
potassium),  and  before  long  the  white  niter  film  will 
appear  on  the  wind  face  of  the  heaps.  It  is  scraped 
off  regularly  ;  the  extracted  earth  being  always  re- 
turned to  the  heap,  and  thus  a  continuous  process  of 
niter-production  becomes  instituted.  Likewise  the 
earth  floor  of  stables  was  dug  up  from  time  to  time 


ORIGIN    AND    OCCURRENCE    OF    NITER. 


211 


in  all  the  villages  of  France  and  the  rest  of  the  con- 
tinent of  Europe  during  the  Napoleonic  wars,  to 
supply  the  niter  for  the  enormous  consumption  of 
gunpowder.  Sweden  is  the  only  country  where  this 
custom  still  prevails. 

However,  the  discovery  of  an  extended  territory 
in  Peru,  under  the  surface  of  which  lies  a  natural 
deposit  of  soda  niter,  has  gradually  produced  a  thor- 
ough revolution  in  the  niter  industry.  The  former 
Peruvian  Province,  Tarapacca,  now  belonging  to 
Chili,  is  formed  by  a  plateau  with  an  average  alti- 

FIG.  61. 


tude  of  3,000  feet.  It  forms  the  first  steps,  so  to 
speak  of  the  giant  stairway  of  the  Andes,  the  highest 
step  of  which  is  26,000  feet.  The  surface  rocks  are 
all  of  volcanic  origin,  being  both  basalt,  porphyry 
and  trachyte.  Between  ridges  of  these  rocks  extend 
flat  basins  whose  surfaces  are  destitute  of  vegetation 
except  a  few  plants  which  have  become  acclimated. 
The  region  is  quite  rainless,  a  perfect  desert.  Fig. 


212  CHEMISTRY    SIMPLIFIED. 

61  is  a  section  through  a  niter  basin,  s,  s  gives  a 
vertical  section  of  the  different  layers ;  a,  top  layer 
of  ashy  gray  sand  and  pebbles,  6,  conglomerate 
in  which  the  same  material  contained  in  the  top 
layer  is  cemented  together  with  clay  and  salt,  c, 
massive  niter,  sometimes  8  to  9  ft.  thick  and  perfectly 
white,  a  mixture  of  sodium  nitrate,  sodium  chlorid, 
potassium  sulfate,  sodium  sulfate,  sodium  iodid, 
sodium  iodate  with  more  or  less  fine  sand  and  clay,  d, 
pure  sodium  chlorid  (common  salt),  e,  clay  and  loam, 
/,  bed  rock-granite,  porphyry,  basalt.  The  natives 
give  to  the  niter  the  name  caliche.  The  mining 
operations  consist  in  sinking  bore  holes  to  the  sur- 
face of  bed  e,  the  clay.  The  diameter  of  the  hole 
admits  a  workman  of  small  stature,  who  widens  out 
a  small  chamber  and  charges  it  with  500  to  600  Ibs. 
of  powder  or  a  corresponding  quantity  of  dynamite. 
The  hole  is  then  filled  first  with  dry,  then  on  top 
with  wet,  sand.  The  explosion  usually  breaks  up  the 
niter  bed  in  a  circle  of  about  90  to  100  feet  in 
diameter.  The  niter  blocks  are  then  sorted  out  and 
transported  to  the  leaching  works  some  distance 
away.  In  1873  the  niter  bed  was  estimated  to  under- 
lie a  territory  of  550  square  miles,  and  each  square 
mile  to  contain  about  four  million  tons  of  niter, 
which  would  give  a  total  of  2,200  millions  of  tons 
or  an  annual  yield  of  two  million  tons  for  a  thous- 
and years.  But  since  the  present  consumption  is 
about  ten  million  tons  per  year,  the  enormous  de- 
posit will  not  last  over  200  years.  How  came  this 
deposit  to  be?  The  nitrogen  must  have  been 


ORIGIN    AND    OCCURRENCE    OF    NITER.  213 

brought  by  the  instrumentality  of  either  plants  or 
animals  or  both ;  our  present  knowledge  admits  of 
no  other  source.  As  we  find  the  Chincha  Islands 
just  off  the  coast  of  Peru,  and  upon  these  islands 
millions  and  millions  of  tons  of  guano,  Indian  word 
for  the  excrements  of  birds,  it  has  been  suggested  by 
some  that  this  depression  or  gap  in  the  Andean 
Mountain  chain  was  used  in  past  ages»as  the  transi- 
tion point  for  the  east-west  migration  of  birds  and 
they  made  a  halting  place  on  the  shores  of  existing 
lakes  (now  dry  desert).  This  theory,  while  account- 
ing for  the  nitrogen,  leaves  out  the  phosphate  con- 
tained in  the  guano.  There  are  no  phosphates  in 
the  niter  beds ;  phosphates  are  much  less  soluble 
than  the  nitrate  of  sodium ;  they  would  surely  be 
found  with  the  niter  if  guano  had  been  the  source 
of  the  nitrogen.  Equally  fallacious  is  the  theory  of 
sea-weeds  as  original  nitrogenous  material.  "  We  do 


CONVERSION    OF    SODA    NITER    INTO    POTASH    NITER. 

Although  Na(N03)  contains  more  (NO3)  per  unit 
weight  than  K(N03),  Na(NO3)  being  85,  KNO3 
being  101,  yet  experiments  proved  the  unsuitability 
of  Na(N03)  for  gun  powder.  Thus  the  conversion 
of  Na(N03)  into  K(N03)  became  necessary.  It 
is  readily  done  by  the  reaction 

Na(N03)  +  KC1  =  K(N03)  +  NaCl. 

Na(N03)  is  produced  in  Chili,  KC1  is  produced 
(see  under  potassium)  in  the  salt  mines  at  Stass- 
furt,  Germany.  Conversion  comprises  the  following 


214 


CHEMISTRY    SIMPLIFIED. 


stages  or  operations :  (1)  Dissolve  the  soda  niter  in 
1.5  parts  of  boiling  water  in  a  large  iron  vessel  or 
open  boiler,  B  (Fig.  62).  (2)  Dissolve  KC1  in  three 
parts  of  water.  (3)  Hang  into  B  a  perforated  sheet- 
iron  vessel,  P,  by  means  of  chain,  C  C,  and  a  crane. 
(4)  Add  the  KC1  to  the  boiling  Na(N03)  solution  in 
quantity  corresponding  to  the  ratio  niter  =  85, 
KC1  =  74.5.  (5)  Common  salt,  NaCl,  will  begin  to 


fall  out  at  once  as  a  fine,  granular  body,  because  it 
is  less  soluble  in  the  given  water  than  either  of  the 
two  others.  (6)  NaCl  crystals  will  collect  in  the 
perforated  or  basket  vessel,  P,  more  and  more  as  the 
liquid  is  boiled  away  to  one-half.  (7)  The  vessel, 
P,  is  lifted  out  and  washed  with  boiling  water, 
which  displaces  the  adhering  niter  liquor.  The 
washings  are  boiled  down  and  added  to  liquid  in  B 
This  liquid  is  run  into  shallow  iron  pans,  where  the 


ORIGIN    AND    OCCURRENCE    OF    NITER.  215 

impure  K(N03)  now  comes  out  as  a.  massive  crystal 
crust  as  the  liquid  cools  down.  (8)  The  mother 
liquor,  being  chiefly  NaCl  with  some  K(N03),  is 
boiled  down,  the  salt  falling  into  basket  as  at  first. 
(9)  The  massive,  impure  K(N03)  is  redissolved  and 
boiled  down  until  no  NaCl  falls,,  and  is  then  run 
into  vats,  where  it  cools  under  constant  agitation. 
The  agitation  causes  the  niter  to  fall-out  in  small, 
loose  crystals  like  granulated  sugar.  The  niter 
meal  is  raked  and  dipped  out,  thrown  upon  drying 
floors,  and  then  packed  into  bags  and  shipped. 
After  this  refining  process  the  niter  still  holds  about 
one-half  per  cent,  of  NaCl,  which  does  not,  however, 
interfere  with  its  further  use  in  powder  making. 
The  NaCl  produced  by  this  process  is  chiefly  used 
for  pickling  meat,  as  the  small  quantity  of  adhering 
niter  is  desirable  as  a  better  preserving  agent  even 
than  the  salt. 


CHAPTER  XIII. 

THE    MANUFACTURE    OF    HYDROGEN    SULFATE 
OR  SULFURIC  ACID  ON  A  COMMERCIAL  SCALE. 

1.  Direct  proof  that  H2S04  results  by  the  union  of 
SO*  with  H20.  Sulfur  disappears  when  heated 
with  concentrated  HNO3.  It  disappears  easier  if 
HC1  is  also  present.  If  the  liquid  be  then  evap- 
orated on  a  water-bath  a  point  will  be  reached  when 
no  further  evaporation  takes  place.  Water  must  be 
added  several  times  and  the  liquid  evaporated  to 
get  rid  of  HC1  and  excess  of  HNO3.  The  residue 
has  all  the  characters  of  hydrogen  sulfate.  Let  the 
action  be  made  with  a  known  weight  of  the  flowers 
of  sulfur,  say  0.5  gram.  Then  let  us  add  water, 
after  the  evaporation  and  also  3  grams  of  pure  lead 
oxyd  (PbO),  and  let  everything  be  transferred  to  a 
clean  porcelain  crucible  of  known  weight,  and  be 
evaporated  to  dry  ness.  We  know  that  lead  vitriol 
will  stand  a  low  red  heat  without  decomposition, 
and  also  that  lead  nitrate  decomposes  below  red 
heat  into  PbO  +  2N02  -f  O2.  If  then  we  heat  the 
crucible  to  redness  until  the  weight  be  constant,  we 
shall  have  the  total  3  grams  of  lead  oxyd,  the  total 
0.5  gram  of  sulfur  and  the  oxygen  which  was  taken 
up  by  the  sulfur  to  form  the  hydrogen  sulfate,  but 
(216) 


MANUFACTURE    OF    HYDROGEN    SULFATE.        217 

there  will  be  no  water,  because  PbO  has  displaced 
the  water  in  H2O.S03  forming  PbO.SO3. 

We  find,  after  ignition,  that  the  contents  of  the 
crucible  weigh  4.25  grams  ;  0.75  gram  of  oxygen  has- 
been  taken  up  by  0.5  sulfur,  for  4.25  —  3.0  —  0.5  = 
0.75  ;  hence  %f  :  °-T7/  ==  0.01563  :  0.0463  ==1:3, 
hence  $03.  The  reaction  between  sulfur  and  hy- 
drogen nitrate  alone  is  :  S+2H(N03)  +  heat  =  H2O 
+  SO3  +  2NO  =  H2(S04)  -f  2NO.  (The  HC1  when 
added  acts  as  a  catalyzer  possibly  through  the 
momentary  formation  of  a  chlorid  of  S.)  Thus  32 
Ibs.  of  S  will  yield  with  126  Ibs.  of  H(N03),  98  Ibs. 
of  H2(S04).  Value  of  1  Ib.  S  =  0.5  cent;  of  1  Ib. 
nitric  acid,  specific  gravity  1.48  —  7.5  cents.  But 
acid  of  1.48  specific  gravity  contains  only  88  per 

cent,  of  H(N03),  hence  1  Ib.  of  HNO3  costs 


88 

-8.52  cents.     Thus  1  Ib.  of  H2(S04),  if  made  by 
this  reaction  would  cost  in  material  alone 

for  s32x°-5=:  Q.16  cent 

'126X85  =11.06  cents. 

forH(N03)—     J±?=10.9  cents 

Jo 

Now,  the  66°  Be.  sulfuric  acid  which  contains  93 
per  cent.  H2S04  is  sold  for  2.5  cents  per  Ib.  or 
nearly  J  of  the  11.06  cents.  The  oxygen  of  the 
niter  is  too  expensive  for  our  purpose.  Supposing 
we  change  S  into  SO2,  by  burning  the  sulfur  in 
air,  the  oxygen  of  which  costs  nothing,  and  then 
conducting  the  SO2  into  the  H(N03),  then  we  obtain 


218  CHEMISTRY    SIMPLIFIED. 

3S02  +  2H(N03)  ==  H20  +  3S03  +  2NO 
and  by  adding  water 

3S02  +  2H(N03)  +  2H20  =  3H2S04  +  2NO. 
By  this  reaction  the  cost  of  materials  will  be  cut 
down  to  ^  or  3.66  cents.     Even  this  is  too  much. 
But  we  have  seen  that  the  gas  NO  becomes  NO2  in 
presence  of  air,  and  that  NO2  reacts  upon  SO2  thus 

SO2  +  NO2  =  SO3  +  NO 

or  SO2  +  H20  -f  NO2  =  H2(S04)  +  NO. 
Deduction  :  The  gas  NO  can  be  made  the  carrier 
of  the  atmospheric  oxygen  or  even  more  pertinently 
the  transfer  agent.  This  reaction,  then,  points  out 
the  road  for  the  cheap  manufacture  of  H2(S04),  for, 
theoretically  we  need  only  to  buy  the  sulfur.  The 
theoretical  conditions  would  become  realized  in 
practice,  if  we  could  burn  the  sulfur  in  pure  oxygen- 
But  the  latter  requires  KC103,  and  turns  out  more 
expensive  even  than  the  niter-oxygen.  The  chem- 
ical engineer  is  forced  to  make  a  compromise 
between  what  is  best  and  what  is  cheapest.  For, 
since  1  volume  SO2  contains  1  volume  of  oxygen 
we  must  admit  for  every  volume  of  sulfur  vapor,  5 
volumes  of  air,  hence  follows  the  mixture  of  5 
volumes,  one  of  which  is  SO2  and  four  are  N.  In 
addition  to  this,  2.5  more  volumes  of  air  must  be 
admitted  to  furnish  the  one-half  volume  required 
for  the  transfer  by  NO  so  that  SO3  may  result. 
Thus  6  volumes  of  indifferent,  or  useless,  nitrogen 
must  be  steadily  removed  from  the  vessel  in 
which  the  transferring  action  takes  place.  This 


MANUFACTURE    OF    HYDROGEN    SULFATE.        219 

cannot  be  done  without  at  the  same  time  re- 
moving the  NO  (the  transfer  agent),  while  the 
H2S04  condenses  to  a  liquid  and  thus  removes 
itself.  The  French  chemist  Gay-Lussac's  ingenuity 
intervened,  however,  and  saved  a  very  large  per- 
centage of  NO  ;  and  thus  made  the  low  price  of  the 
sulfuric  acid  possible,  while  yet  leaving  a  margin 
of  profit  in  the  manufacture.  Another  saving  in 
the  cost  came  in  with  the  substitution  of  pyrite  for 
sulfur.  The  mineral  pyrite  is  FeS2  and  contains 
2  X  32  =  64  sulfur  for  every  56  of  iron,  or  1 
pyrite  =  0.533  of  sulfur,  a  little  more  than  J  its 
weight.  As  some  sulfur  always  remains  with  the 
iron,  we  may  say  that  pure  pyrite  yields  50  per 
cent,  of  sulfur  in  form  of  SO2  if  properly  handled. 
The  action  occurs  thus  : 

2FeS2  +  110  =  Fe203  +  4S02,  (if  complete.) 
240pyrite+176  oxygen=160  iron  oxyd-j-256  sulfur 
dioxyd.  If  burnt  in  air  we  have  an  addition  of  4 
vols.  of  N  =  616  nitrogen.  These  numbers,  of 
course  mean  weight.  1  c.c.  of  SO2  weighs  0.00285 
gram  hence 


256  grams  SO'  =  -  =  89824  c.c.  =  89.8 

liters. 

1  c.c.  of  N  weighs  =  0.001256  gram,  hence  616 
grams 

N  =  _  —  _  =  490.4  liters. 
0.001256 

For  1  liter  of  SO2  we  have  about  5  liters  of  nitro- 


220  CHEMISTRY    SIMPLIFIED. 

gen.  But  we  must  provide  with  this  also  the  oxygen 
necessary  to  make  SO2  into  SO3.  SO2  contains  J 
volume  S  and  one  volume  0,  hence  1  volume  SO2 
requires  J  volume  of  0  or  2J  volumes  of  air,  thus 
making  a  total  of  1  volume  SO2  +  5  volumes  of 
N  +  2J  volumes  of  air  =  8.5  volumes,  leaving  the 
pyrite  burners.  In  this  mixture  of  gases  the  volume 
percentage  of  SO2  is  11.76.  If  this  percentage  falls 
below  4,  the  conversion  becomes  incomplete,  as  de- 
monstrated by  experience.  As  was  to  be  expected, 
experience  showed  the  necessity  of  an  excess  of  oxy- 
gen over  that  which  the  calculation  demands. 
Hence  the  average  composition  of  the  gas  mixture, 
in  leaving  the  pyrite  burner,  is  like  this :  N  =  81 ; 
SO2  =  8.8;  0  =  9.6  in  100  volumes.  The  plant 
(equal  to  what  in  laboratory  speech  we  call  appa- 
ratus) for  the  manufacture  of  sulfuric  acid  comprises 
the  following  principal  parts:  1,  the  burners;  2, 
the  Glover  tower;  3,  the  lead  chamber;  4,  the  Gay- 
Lussac  tower ;  5,  the  concentrating  outfit.  The  diagram, 
Fig.  63,  shows  the  arrangement  of  the  plant  in  ground 
plan.  EBB  are  three  burners  or  kilns  for  pyrite ; 
D  is  the  dust  chamber,  of  brickwork  for  the  purifi- 
cation from  solid  particles  of  the  gas  ;  G  is  the  Glover 
tower ;  MC  is  the  mixing  lead-chamber  and  Cf  is 
the  main  lead-chamber;  GL  is  the  Gay-Lussac 
tower  with  the  chimney  attachment  Ch,  from  which 
the  waste  gases  escape  into  the  air.  In  Fig.  64  the 
plant  appears  in  sectional  elevation.  The  pyrite 
burner  shows  as  a  rectangular  shaft  or  stack  about 
12  feet  high  and  built  of  fire-brick.  Several  of  them 


MANUFACTURE    OF    HYDROGEN    SULFATE.        221 


Pffi 

CD       CO      CO 

,  I 


222  CHEMISTRY   SIMPLIFIED. 

are  generally  built  close  together  in  a  row  (see  ground 
plan).  Two  opposite  doors  1,  1  allow  the  iron  oxyd 
to  be  drawn  out,  while  a  bell  and  hopper  arrange- 
ment, 2,  serves  to  introduce  the  pyrite,  without  los- 
ing any  gas.  At  3  is  a  strong  cast-iron  grate  in  the 
form  of  a  cone  ;  through  the  canal  4  air  is  admitted 
to  this  grate.  Small  inlets  5,  5,  5  admit  air  to  the 
upper  part,  when  necessary.  The  burner  is  started 
with  a  wood  fire,  until  the  lower  furnace  walls  are 
at  red  heat.  Then  small  charges  of  pyrite  are  intro- 
duced until  the  stack  is  full  to  within  6  feet  of  the 
top.  The  burning  of  the  sulfur  into  SO2  furnishes  all 
of  the  heat  needed  from  this  period  on.  A  1-foot  iron 
pipe  takes  the  gases  from  each  burner  into  the  dust 
chamber  D  which  is  built  of  common  brick  ;  two 
vertical  partitions  7,  8  divide  the  chamber  into  three 
sections  and  force  the  gases  to  a  broken  up  and  down 
course  shown  by  the  arrows.  Doors  9,  9  permit  the 
removal  of  the  ore-dust  from  time  to  time.  A  two 
foot  iron  pipe,  10,  takes  the  gases  to  the  Glover  tower 
G  so  named  after  its  inventor.  It  forms  a  brick 
stack  of  square  section  ;  the  inside  is  lined  with  hard 
glazed  bricks  which  resist  the  action  of  the  acids. 
A  perforated  arch  of  such  bricks,  11,  serves  to  sup- 
port a  structure  of  loose,  hard,  stoneware  bricks  and 
cylinders  12.  The  idea  is  to  present  a  very  large 
surface  over  which  the  acid  which  comes  from  tank 
T  above  the  tower,  can  spread  and  come  in  contact 
with  the  hot  gases. 

Purpose  and  function  of  the  Glover  tower.     (1)  To 
cool  down  the  gases  to  the  temperature  needed  in 


MANUFACTURE    OF    HYDROGEN    SULFATE.        223 

the  chambers.  (2)  To  utilize  the  nitrose  from  the 
Gay-Lussac  tower.  The  term  "  nitrose  "  was  intro- 
duced to  designate  the  combination  H2S04.NO. 
The  nitrose  is  pumped  from  the  tank,  T,  under  the 
Gay-Lussac  tower,  by  means  of  air  pressure  through 
lead  pipes  into  the  one-half  of  the  tank,  T,  on  top  of 
the  Glover,  and  the  dilute  acid  formed  in  the  cham- 
ber, MCj  is  pumped  through  pipe  line,  13,  into  the 
other  half  of  T.  From  these  tanks  properly  regu- 
lated streams  pass  through  air-tight  openings  of  the 
top  of  the  tower  upon  the  cylinder  which  forms  the 
apex  of  the  stoneware  pyramid.  Here  the  concen- 
trated nitrose  in  mixing  with  the  dilute  chamber 
acid  sets  free  the  NO,  while  the  now  semi-concen- 
trated acid  in  running  over  the  large  brick  surface 
comes  to  boiling  in  contact  with  the  hot  burner 
gases,  splits  into  concentrated  acid,  which  collects 
below  the  arch,  and  is  drawn  thence  by  automatic 
syphon  in  the  tank,  T,  under  the  tower,  whence  it 
is  pumped  to  the  top  of  the  Gay-Lussac  tower  to 
begin  a  new  circuit  of  absorbing  NO,  etc.,  ad  infini- 
tum.  Aqueous  vapor  from  the  boiling  acid  in  the 
meantime  has  mingled  with  the  liberated  NO,  and 
with  the  other  gases  passes  through  pipe,  lh  into  the 
mixing  chamber,  MC.  Here  the  action  sets  in  : 

SO2  +  0  +  NO  +  H20  =  H2(S04)  +  NO. 

The  H2S04  +  water  vapor  forms  a  dense  white  fog, 
which  becomes  liquid  when  it  strikes  a  cool  surface ; 
thus  the  principal  precipitation  occurs  along  the 
sides  of  the  chamber,  whence  the  acid  runs  down 


224  CHEMISTRY    SIMPLIFIED. 

into  the  leaden  pan,  15.  Owing  to  the  misty,  foggy 
condition  of  the  acid  such  an  immense  size  of  the 
chambers  is  required.  From  an  average  of  fifteen 
English  works,  the  chamber  space  is  21  cubic  feet  for 
one  pound  of  sulfur  burned  in  24  hours.  A  plant, 
therefore,  which  is  to  produce  five  tons  of  66°  Be', 
acid  in  24  hours  will  require  a  chamber  space 

V  =  10000  X  0.94  X  21  X  ft  =  64457  cubic  feet. 
Making  the  chamber's  cross  section  20'  wide  by 
16'  high  we  get  an  area  of  320  square  feet,  and 
hence  £f|{p-  =  201.4  feet.  Such  a  length  would  be 
best  broken  into  3  chambers ;  to  wit :  A  mixing 
chamber  50  feet  long,  a  main  chamber  101.4  feet 
long,  an  end  chamber  50  feet  long.  The  cost  of 
the  lead  for  these  three  chambers  will  be  arrived  at 
thus : 

2  sides  (201.4  X  16  each)      =  6445  square  feet. 

1  top  201.4  X  20  =  4028  square  feet. 

1  bottom  201.4  X  22  -  4430  square  feet. 

6  ends  (20  X  16  each)  =  1920  square  feet. 

For  Gay-Lussac  tower  and 

connection  pipes  =  2000  square  feet. 


Total  18823  square  feet. 

Sheet-lead  is  rolled  of  many  thicknesses,  which  are 
counted  as  so  many  pounds  per  square  foot,  hence 
1  lb.,  2  Ibs.,  3  Ibs.,  ...  12  Ibs.  sheet  lead.  Six 
Ibs.  per  square  foot  is  thick  enough  for  the  cham- 
bers, hence  the  total  weight  of  lead  will  be  18823  X 
6  =  112938  pounds,  and  at  6  cents  per  lb.,  this 
represents  a  cost  of  $6,776.28. 


MANUFACTURE    OF    HYDROGEN    SULFATE.        225 


The  Gay—Lussac  tower  and  its  functions.  The  pur- 
pose is  to  expose  a  maximum  of  surface  covered 
with  a  moving  film  of  concentrated  H2SO4  to  the 
ascending  gas  mixture  from  the  last  chamber. 
When  thus  exposed  the  H2S04  will  absorb  NO. 
The  absorption  is  proportional  to  the  concentration 


FIG.  65. 


FIG.  66. 


of  the  acid.  Much  aqueous  vapor  is  in  the  gas 
mixture,  which  will  be  absorbed,  and  hence  dilute 
the  acid,  lowering  its  capacity  for  NO.  Thus  comes 
the  more  recent  practice  of  setting-  up  two  towers, 
one  for  drying  the  gases,  the  second  for  the  absorp- 
tion proper.  A,  Fig.  65,  is  a  vertical  section  of  the 
tower  as  commonly  in  use.  Over  a  perforated  arch 
15 


226 


CHEMISTRY    SIMPLIFIED. 


1  there  lies  a  column  of  coke-pieces  of  fist  size. 
From  a  shallow  tray  #,  studded  with  many  small 
dripping  tubes  falls  the  concentrated  acid  over  the 
coke,  soaks  into  the  latter  and  finally  comes  out  as 
nitrose  through  the  arch  1  into  a  tank  T"  under 
the  tower.  The  gases  enter  I  and  leave  at  II  into 
the  chimney  Ch.  A  pipe  8  passes  through  the 
leaden  top  (tightly)  and  feeds  the  acid  from  the 
tank  T  into  the  tray  2. 

A  more  perfect  arrangement  is  shown  in  Fig. 
66,  known  as  the  Lunge-Rohrmann  plate  column. 
The  tower  is  of  sheet-lead  in  wooden  or  iron  frame. 
Supporting  ledges  4,  4  are  provided,  fused  on  (burned 
on  in  technical  speech)  along  the  walls  or  sides. 

FIG.  67. 


Similarly  a  central  support  5  is  provided  of  glazed 
stoneware.  In  the  cross  section  Fig.  67,  we  see  that 
there  are  four  plates,  each  one  perforated  by  16 
holes,  and  each  hole  enclosed  within  a  small  square 
area  acting  as  a  shallow  reservoir.  It  is  claimed 
for  this  system  that  it  is  quite  superior  in  action  to 
the  coke  filling,  inasmuch  as  the  surface  is  very 
large  and  yet  regular,  especially  when  the  perfora- 
tions of  the  alternate  plates  are  not  directly  above 


MANUFACTURE    OF    HYDROGEN    SULFATE.        227 


one  another,  but  so  that  the  liquid  drops  from  *the 
upper  hole  upon  the  dividing  ridge  of  the  lower 
panel. 

Concentration  of  the  chamber  acid.  Experience 
demands  that  enough  water  be  delivered  to  the 
chamber,  as  steam  or  as  spray,  so  f  that  the  con- 
densing acid  corresponds  about  to  the  tri-hydrate 
H2(SO4).3H20.  This  liquid's  specific  gravity  is 
50°  B£.  corresponding  to  64  per  cent.  H2S04.  For 
many  purposes  such  a  strength  is  sufficient,  for  others 
it  must  be  made  as  strong  as  possible.  Between  the 


FIG.  68. 


FIG.  69. 


two  extremes  lies  the  strength  of  60°  Be\  =  80  per 
cent.  H2(SO)4.  This  grade  is  known  in  the  trade 
as  pan  acid,  because  it  is  obtained  by  heating  the 
chamber  acid  in  leaden  pans.  At  a  higher  concen- 
tration than  60  per  cent.,  the  hot  acid  begins  to  at- 


228  CHEMISTRY    SIMPLIFIED. 

tack  the  lead  of  the  pan,  making  white  lead  sulfate 
and  SO 2 .  The  further  concentration  must  be  carried 
on  in  retorts  of  either  glass  or  platinum.  Large 
glass  retorts  break  easily  ;  those  of  platinum  are 
very  costly.  Hence  a  combination  of  the  two  is 
sometimes  used  in  which  the  bottom  is  of  platinum, 
the  top  or  helmet  of  glass,  or  the  helmet  of  lead. 
Figs.  68  and  69  illustrate  the  Gridley  system  of  con- 
centrating in  glass  retorts  by  continuous  process. 
Fig.  68  shows  one  retort  R  in  elevation,  while  Fig., 
69  is  a  ground  plan  showing  the  combination  of  4 
retorts  into  a  self-acting  system.  We  see  the  retort  set 
into  an  iron  basin  with  a  layer  of  coarse  sand  between 
iron  and  glass.  Heat  is  applied  to  each  retort  sepa- 
rately \yy  a  Bunsen  burner  of  sufficient  size.  Each 
retort  has  an  inlet  for  the  weak  acid  1  and  a  syphon 
outlet  2  (see  ground  plan  specially).  The  helmet  H 
carries  the  weak-acid  distillate  into  the  pipe  P  of 
sheet-lead.  As  each  retort  of  a  set  stands  higher 
than  its  oneside  neighbor  and  lower  than  the  other 
neighbor,  the  acid  of  steadily  increasing  strength 
flows  from  Rl  to  R±  and  from  R4  into  the  cooling 
worm  W,  which  lies  in  a  stream  of  running  water ; 
from  the  worm  the  acid  of  65.5°  Be',  flows  into  the 
carboy  K.  By  general  agreement  this  is  the  cheapest 
way  of  concentrating  sulmric  acid.  But  only  acid 
of  92  to  93  per  cent,  can  be  made  by  it. 

In  Figs.  70  and  71  we  see  an  all-platinum  still  of 
the  most  modern  construction,  for  making  acid  of 
98  to  99  per  cent.  H2S04,  as  furnished  by  the  firm 
of  Lemaire  and  Co.  of  Paris.  The  strenuous  effort 


MANUFACTURE    OF    HYDROGEN    SULFATE.        229 

necessary  is  divided  between  two  stills  A,  B,  each 
upon  a  separate  fire-place  Fy  F'.  Each  still  is  a  flat, 
elliptical  vessel,  Fig.  71,  ground  plan.  The  still  is 
in  three  detachable  pieces,  1  the  pan,  #  the  lid,  3  the 
helmet  and  snout  to  carry  off  the  vapors.  (Snout 
not  shown.)  The  older  forms  of  still  are  circular. 
The  elongated  form  is  chosen  because  it  gives  a 
more  economical  use  of  the  heat.  The  pan  1  is  dif- 
ferent in  the  two  stills.  In  A  the  pan  has  4  longi- 


FIG.  70. 


FIG.  71. 


tudinal  compartments,  it  consisting  in  fact  of  2  con- 
centric pans,  the  inner  about  {  inch  deeper  than  the 
outer.  Thus  a  larger  surface  of  evaporation  is 
gained.  Now  supposing  the  acid  of  56°  Be.  being 
fed  into  A  at  the  point  /,  it  will  flow  along  the 
outer  compartment  as  the  arrows  point.  The  cur- 
rent will  pass  through  an  opening  in  the  partition 
at  a  into  the  inner  compartment  and  circulate  to  b, 
whence  the  syphon  tube  S,  S,  S  will  draw  it  into  the 
still  B  at  G.  The  partitions  in  B  are  transverse  and 
do  not  touch  the  bottom,  but  leave  f  inch  opening. 
This  is  necessary  for  cleansing  the  pan  as  from  the 


230  CHEMISTRY    SIMPLIFIED. 

highest  concentrated  acid  a  small  percentage  of 
iron  sulfate  precipitates.  But  here  too  a  meander- 
ing of  the  current  is  brought  about  as  the  arrows 
indicate.  At  d  another  syphon  tube  takes  the  con- 
centrated acid  to  the  cooler  C  whence  it  goes  either 
to  the  carboys  or  iron  tanks,  because  at  ordinary 
temperatures  the  strongest  H2S04  does  not  act  upon 
iron.  It  is  found  that  by  the  best  care  the  platinum 
will  dissolve  in  the  strong  acid  at  about  the  rate  of 
1  gram  per  ton  of  acid.  For  five  tons  daily  produc- 
tion the  bottom  pan  of  the  still  will  therefore  lose 
300  X  5  =  1500  grams  a  year  and  can  at  best  last  2 
years. 

MANUFACTURE    OF    OIL    OF    VITRIOL    AND    SULPHURIC 
ACID    BY    THE    CONTACT    PRINCIPLE 

1.  Oil  of  vitriol  and  SOB  by  Winkler's  method. 
Fundamental  facts  represented  by  the  following 
equations : 

(a)  H2S04  (93  per  cent,  acid)  -f  contact  surface 
at  yellow  heat  =  H20  +  SO2  +  0  +  aq. 

(b)  H20  +  SO2 .+  0  +  aq.  +  cold  contact  sur- 
face ==  Water  +  (SO2  -f  0),  (moist  gases). 

(c)  SO2   +  0  +  moisture  -+-  spray    of  concen- 
trated  acid  =  SO2  +  0  +  less  cone.  H2S04   (dry 


(d)  SO2  -f  0  (dry)  +  platinated  asbestus  (at  dull 
red  heat)  ==  SO8  (as  white  vapor). 

(e)  Spray  of  H2S04  (93  per  cent,  acid.)  +  nSO3 
=  H2S04  +  nSO3  =;  oil  of  vitriol, 


MANUFACTURE    OF    HYDROGEN    SULFATE.        231 

In  words :  93  per  cent,  acid  is  broken  up  into 
H20  +  SO2  -f  0  by  being  spread  over  a  highly 
heated  surface  of  acid-resisting  material.  The  re- 
sulting mixture  of  water  vapor,  sulfur  dioxyd  and 
oxygen  is  passed  through  cooling  tubes  in  which 
most  of  the  water  vapor  becomes  liquid  water.  The 
gases  are  then  sent  over  an  extended  surface  of  93 
per  cent,  acid  (a  fine  spray)  by  which  the  water- 
vapor  becomes  fully  absorbed,  and  lastly  the  mix- 
ture of  dry  SO2  -f-  0  is  passed  through  a  cylinder 
heated  up  to  dull  red  heat,  and  filled  with 
asbestus  over  which  a  film  of  platinum  has  been 
spread.  Here  then  the  platinum  is  the  carrier  for 
the  oxygen,  or  the  transfer  agent,  as  in  the  ordinary 
process  the  NO  is  the  transfer  agent. 

Finally  the  SO3  can  either  be  condensed  in  glass 
vessels  as  solid,  silky,  trioxyd,  or  it  can  be  sent 
against  a  fine  spray  of  93  per  cent,  acid,  in  which 
the  SO3  dissolves.  By  increasing  or  decreasing  the 
volume  of  the  spray  one  will  be  able  to  get  oil  of 
vitriol  (fuming  sulfuric  acid)  of  any  degree  of 
strength.  Simple  as  the  process  appears,  there  are 
considerable  technical  difficulties,  notably  the  diffi- 
culty of  keeping  the  apparatus  from  rapid  deteriora- 
tion. 

2.  Making  sulfuric  acid  by  contact  directly  from  the 
pyrite.  The  principle  which  underlies  this  plan  is 
the  same  as  in  the  preceeding.  Why  can  we  not 
make  H2S04  by  passing  the  mixture  of  gases  com- 
ing from  the  pyrite  burner,  namely  nitrogen,  sulfur 
dioxyd,  and  oxygen,  directly  over  platinated  a$r 


232  CHEMISTRY    SIMPLIFIED. 

bestus?  The  question  has  been  asked.  At  first 
sight  there  seems  to  be  no  valid  objection  and  the  ex- 
periment proves  the  feasibility.  The  cost  should 
certainly  be  less,  no  lead  chambers,  no  expensive 
stills  required  for  the  concentration.  Works  have 
been  built  on  this  plan  and  run  for  a  number  of 
years.  It  seems  however  that  the  conversion  of  SO2 
into  SO3  is  incomplete  owing  to  the  presence  of  the 
large  volume  of  nitrogen.  Likewise  the  condensa- 
tion of  the  SO3  in  this  diluted  condition  is  very  diffi- 
cult and  gives  much  weak  acid,  which  has  to  be  con- 
centrated after  all.  Thus  the  chamber  method  is 
not  likely  to  become  superseded  for  some  time,  or 
until  the  present  difficulties  of  the  contact  method 
have  been  finally  overcome  by  ingenuity  and  ex- 
perience. 


CHAPTER  XIV. 
OTHER  COMPOUNDS  OF  SULFUR. 

We  may  say  that  sulfur  posesses  a  strong  leaning 
or  affinity  towards  combination  with  the  metals 
nearly  equal  in  this  respect  to  oxygen  and  chlorine. 
The  product  of  the  union  we  call  sulfid. 

CuS  CuO  CuCl2 

Copper  Sulfid  Copper  Oxyd  Copper  Chlorid. 
Oxyds  and  sulfids  are  mostly  insoluble  in  water ; 
chlorids  are  mostly  soluble  in  water.  It  follows  that 
the  so-called  metallic  ores  are  either  sulfids  or  oxyds. 
Thus  the  iron  ores  are  oxyds  and  sulfids :  Fe203, 
Fe304 ;  and  FeS2.  The  copper  ores  are  Cu2S,  CuS, 
CuFeS2,  Cu20,  CuO  (exceptionally  native  copper, 
Cu).  The  lead  ore  is  PbS,  zinc  ores  are  ZnS  and 
ZnO.  Tin  ores  are  CuSnS2  and  SnO2.  The  only 
exception  among  the  common  metals  is  aluminum ; 
of  it  only  the  oxyd  A1203  is  known  but  no  com- 
bination with  sulfur,  except  in  the  form  of  a  sulfate, 
A12(S04)3.  This  means  that  aluminum  has  no  af- 
finity for  sulfur  at  ordinary  temperature  and  in 
water  solutions.  In  a  general  way  wre  conclude  that 
nature  utilizes  the  affinity  between  sulfur  and  the 
metals  to  concentrate  the  latter  within  the  rocks  and 
thus  make  it  possible  for  man  to  mine  and  extract 
them  at  a  profit.  Example :  Rub  together  with 
(J233) 


234 


CHEMISTRY    SIMPLIFIED, 


mortar  and  pestle,  1,  a  drop  of  mercury  and  sulfur  ; 
2,  finely  divided  metallic  copper  and  sulfur.  In 
either  case  a  new,  black  substance  is  formed,  tbe 
sulfids  of  mercury  and  copper.  Gentle  beat  in  a 
closed  vessel  converts  the  black  sulfid  of  mercury 
into  a  dark-red  sulfid  of  the  same  composition  and 
when  ground  fine  it  is  called  vermilion. 

The  copper  sulfid  CuS  has  a  blue  color  ;  it  cor- 
responds to  the  natural  mineral  covellite  or  indigo 
copper.  Kept  at  a  red  heat  in  a  glass  tube,  which 
is  closed  at  one  end,  it  changes  into  the  bright  grey 
sulfid  Cu2S  thus  : 

2CuS  +  red  heat  =  Cu2S  +  S 

one-half  of  the  sulfur  subliming  into  the  cooler  part 
of  the  tube. 

Hydrogen  sulfid  (old  name  sulphuretted  hydrogen). 

FIG.  72. 


In  acting  with  dilute  H2S04  or  dilute  HO  upon 
iron  sulfid  or  zinc  sulfid  a  very  peculiar  odor  ap- 
pears, due  to  a  rapidly  generating  gas.  Let  A,  Fig. 
72,  be  a  flask  holding  about  250  c.c.,  fitted  with 
stopper  funnel  tube  and  evolution  tube.  Bring  into 
it  20  grams  of  iron  sulfid  (FeS)  anil  allow  the  acid 
to  fall  in  drops  from  the  funnel.  (5  %  H2S04  must 


OTHER  COMPOUNDS  OF  SULFUR. 


235 


be  used).  B  is  the  wash  tube  with  water  and  C  is 
a  U-tube  filled  with  CaCl2  in  small  pea  size.  The 
gas  will  issue  dry  and  pure  at  the  narrow  opening 
1.  If  a  match  be  applied  the  gas  will  burn  with  a 
pale  blue  flame  and  if  a  dish  D  with  clean  undressed 
face  and  containing  cold  water  be  held  into  the 
flame,  drops  of  colorless  liquid  (water)  and  yellow 
sulfur  will  be  precipitated  upon  the  dish  D,  whilst 
the  pungent  odor  of  SO2  is  given  off.  Hence  the 
gas  must  be  composed  of  S  and  H. 

Proof  that  the  compound  is  H2S.  Let  the  gas  enter 
the  knee-tube,  (Fig.  73),  over  mercury,  until  the 
latter's  level  is  below  the  knee  ;  mark  the  level  with 

FIG.  73. 


sticker,  M.     Introduce  a  piece  of  tin,  S,  and  shove 
it  to  near  the  end  of  the  knee-tube.     Bring  S  to  red 
heat  with  lamp.     Tin  unites  with  the  sulfur,  forming 
brown  SnS.     After  cooling  we  find  volume  of  gas 
unchanged.     We  reason  since  1  volume  HnSm  con- 
tains 1  volume  H,  then 
Weight  of  1  volume  HnSm  =  1.521 
Peduct  wt.  of  1  vol.  H  -  .089 

1.432  ==  weight  of  S. 


236  CHEMISTRY    SIMPLIFIED. 

But  1.432  is  equal  to  the  wt.  of  \  vol.  sulfur,  hence 
one  vol.  HnSm  contains  1  vol.  of  H  +  J  vol.  S,  or 
2  vols.  of  H  +  1  vol.  S— the  symbol  is  IPS.  100 
grams  of  H2S  contain  S  =  94.2  ;  H  =  5,8  grams. 
Now  we  can  write  the  equation  of  formation  : 

FeS  +  H2S04  ==  FeSO4  +  IPS 
FeS  +  2HC1  =  Fed2  +  H2S. 

Generation  of  H2S  in  a  steady  current  at  the  mini- 
mum of  cost.  This  is  a  very  important  problem, 
because  in  all  analyses,  both  qualitative  and  quan- 
titative, IPS  must  be  used.  Different  forms  of 
apparatus  have  been  described  by  inventors.  Of 
all  those  the  Koenig's  apparatus  serves  the  purpose 
best.  It  has  already  been  described  on  pp.  61  to 
63,  Fig.  28,  for  the  generation  of  chlorine  gas  in 
a  steady,  long-continued  current.  The  apparatus  is 
universal,  may  be  used  whenever  a  gas  is  to  be 
produced  from  a  solid  by  means  of  a  liquid  acid. 
Read  over  the  description  on  pages  61  to  63,  with 
the  following  changes :  The  generating  tube,  Gr,  is 
to  be  charged  with  pieces  of  iron  sulfid,  FeS,  of 
hazel-nut  to  pea  size,  the  funnel  being  removed,  up 
to  the  end  of  the  funnel  tube.  (For  chlorine  we 
only  fill  the  tube  one-third.)  The  funnel  bulb  con- 
tains 5  per  cent.  IPSO4  (never  any  stronger),  27 
c.c.  of  concentrated  H2S04  in  1000  c.c.  of  water. 
This  dilute  acid  acts  upon  FeS  at  ordinary  temper- 
ture,  but  more  energetically  at  60°  C.,  to  which  tem- 
perature the  small  flame  at  b  heats  the  water  in  the 
jacket,  J.  Regulate  the  stop-cock  at  F  so  that  a  drop 


OTHER  COMPOUNDS  OF  SULFUR.       237 

of  acid  will  issue  per  second.  The  gas  will  then 
flow  from  the  goose-neck,  L,  in  a  strong,  even  cur- 
rent. The  other  product,  which  is  a  water  solution 
of  FeSO4  with  a  small  quantity  of  free  acid,  will  be 
discharged  through  the  rubber  tube,  R,  into  the  flask, 
IF.  Thus  the  acid  from  above  will  act  upon  a 
material  surface  always  clean,  always  under  equal 
conditions,  and  hence  produce  the  same  quantity  of 
gas  per  minute. 

Note.  The  pressure  of  the  gas  is  equal  to  a  col- 
umn of  water  of  the  length  of  the  funnel  tube, 
provided  that  the  length  of  the  tube,  R,  from  its 
lowest  point  in  the  bend  to  the  discharge  at  P  be 
equal  to  the  length  of  the  funnel  tube  or  greater. 
If  you  should  connect  the  rubber  from  the  goose- 
neck to  a  long  tube  and  dip  the  latter  to  the  bottom 
of  a  high  beaker-glass  filled  with  water,  so  that  the 
length  of  the  water  column  be  greater  than  the 
length  of  the  funnel  tube,  then  the  gas  will  not  go 
through  the  liquid,  as  it  should  do,  but  it  will 
escape  through  the  funnel  or  at  P.  The  funnel  can 
be  supplied  from  a  large  bottle  by  means  of  a  syphon 
and  a  pinch-cock  or  a  glass  stop-cock.  The  funnel 
holds  sufficient  acid  for  any  ordinary  operation  in 
analysis.  One  often  neglects  to  look  after  things  at 
the  right  time,  and  so  in  this  case  the  whole  charge 
of  iron  sulfid  might  be  used  up  by  sheer  neglect  if 
the  acid  supply  kept  on  running. 

Properties  of  H2S.  Strong,  unpleasant  odor. 
Colorless.  At  11°  C.  under  a  pressure  of  15  atmos- 
pheres, 15  X  15  =  225  Ibs.  per  square  inch,  the  gas 


238  CHEMISTRY    SIMPLIFIED. 

becomes  a  mobile,  colorless  liquid.  The  latter  be- 
comes a  white,  snow-like  mass  of  crystals  at  —  85°  C. 
The  gas  acts  as  a  poison  on  man  and  animals,  pro- 
ducing faintness,  headache  ;  if  persistently  breathed 
it  causes  death.  A  horse  was  placed  in  a  large  room 
which  had  been  made  thoroughly  air-tight.  One- 
half  per  cent,  by  volume  of  EPS  was  mixed  with 
the  air  of  the  room,  then  closed.  The  horse  died  in 
15  minutes.  Always  generate  the  gas  under  a  well- 
drawing  hood  or  in  the  open  air.  One  volume  H2S 
weighs  1.180  if  the  same  volume  of  air  weighs  1.000. 
By  calculation  the  specific  gravity  is  1.1747  when 
air  =  1,  and  18  for  H  =  1.  One  c.c.  of  air  weighs 
0.001293  gram,  therefore  1  c.c.  IPS  will  weigh 
0.001293  X  1.180  —  0.001526  at  0°  C.  and  760  mm. 
mercury  pressure. 

One  volume  water  at  15°  C.  absorbs  nearly  three 
volumes  EPS.  The  resulting  solution  contains 
0.001526  X  3  X  100-0.4578  p.  c.  of  H2S  by  weight, 
about  0.5  per  cent.,  and  is  named  H2S  water.  The 
solution  does  riot  keep.  It  decomposes  rapidly  in 
the  sunlight,  thus  EPS  +  water  -f  0  +  sunlight  = 
S  -f-  EPO  +  water.  It  will  keep  longer  if  the  water 
has  been  boiled,  then  cooled  quickly,  before  passing 
the  EPS  into  it,  and  if  the  bottle  is  then  sealed 
air-tight  before  the  oxygen  of  the  air  can  dissolve 
again  in  the  water.  Brown-glass  bottles  are  best, 
because  the  active  sun  rays  do  not  penetrate  much 
through  such  glass.  EPS  water  freshly  prepared  is 
a  very  handy  reagent  both  in  qualitative  and 
quantitative  work.  The  EPS  water  shows  slight 


OTHER  COMPOUNDS  OP  SULFUR.       239 

add  action  on   litmus.     The   gas   itself  decomposes 
more  readily  than  H20,  thus  : 

H2S  in  red-hot  glass  tube  =  H2  +  S  (sulfur  de- 
posits). 
IPS  H-  H2S04  =  H2  -f  S  (sulfur  floats  on  the  acid). 

H2S  +  electric  spark  =  IP  +  S  (Put  10  c.c.  of  gas 
into  eudiometer  over  mercury  and  let*  the  spark  pass 
over ;  sulfur  deposits  as  a  snowy  cloud  and  10  c.c. 
of  hydrogen  are  left.  This  is  another  proof  of  its 
composition  of  1  vol.  H  -f-  J  vol.  S.) 

Because  concentrated  H2S04  decomposes  the  gas, 
we  reason  that  one  must  not  use  H2S04  as  a  dryer, 
but  CaCl2  instead,  for  this  gas. 

ACTION    OF    H2S    UPON     THE     ALKALINE    HYDROXYDS. 

The  gas  is  eagerly  absorbed  by  both  weak  and 
strong  solutions  of  KOH,  NaOH,  NH4OH. 

(a)  Action  of  H2S  upon  K(OH)  in  water  at  air 
temperature. 

IPS  +  K(OH)  ==  K(SH)  +  H20  and  IPS  + 
2K(OH)  =  K2S  -|-  2H20.  Dissolve  about  5  grams 
of  KOH  in  25  c.c.  of  water.  Divide  the  liquid  into 
2  equal  parts  in  two  test-tubes.  Let  IPS  pass  into 
one  of  the  tubes  until  there  is  no  further  absorption, 
that  is,  until  the  size  of  the  bubbles  does  not  di- 
minish in  the  ascent  through  the  liquid,  and  you 
smell  the  IPS  strongly.  Then  the  colorless  liquid 
will  contain  K(SH),  potassium  sulfohydroxyd.  Now 
pour  the  contents  of  the  other  tube  into  the  first  and 
you  will  have 

K(HS)  +  KHO  =  K2S  +  IPO. 


240  CHEMISTRY    SIMPLIFIED. 

The  solution  of  potassium  sulfid  is  likewise  a  color- 
less liquid.  The  properties  of  the  two  bodies  are 
not  quite  alike.  Both,  by  gentle  evaporation  over 
H2S04  in  a  dessicator  (a  glass  vessel  with  a  ground 
rim  and  ground  cover  or  plate  of  glass),  give  crys- 
tals, but  they  do  not  belong  to  the  same  system. 

K(SH)  can  stand  red  heat  without  decomposition 
if  made  in  the  following  way  in  a  glass  retort,  no 
water  being  present : 

K2C03  +  2H2S  +  red    heat  =  2K(SH)  +  CO2  + 

H20. 

In  this  respect  it  acts  like  the  hydroxyd  K(OH). 
It  is  a  sulfo  base,  which  can  form  with  sulfo  acids, 
sulfo  salts. 

(b)  Action  of  H2Supon  Na(HO). 

H2S  +  Na(OH)  +  water  =  Na(SH)  +  H20. 
IPS  +  2Na(OH)  +  water  =  Na2S  +  2H20  +  water. 
They  act  like  the  potassium  compounds. 

(c)  Action  ofH^Supon  NH4(HO). 

H2S  +  NH4(HO)  =  NH4(SH)  -f  IPO. 
H2S  +  2NH4(HO)  =  (NH4)2S  +  2H20. 

Both  colorless  solutions. 

(d)  Action  of  H2S  upon  Ca(HO)2. 

Make  2  grams  of  quicklime  into  milk  of  lime 
with  20  c.c.  of  water  and  pass  H2S  into  solution 
until  saturated  ;  the  solution  becomes  clear  in  meas- 
ure as  the  hydroxyd  passes  into  the  sulfohydrate, 
thus 

Ca(HO)2  +  2H2S  =  Ca(SH)2  +  H20. 


OTHER  COMPOUNDS  OF  SULFUR.       241 

The  solution  of  the  sulfohydrate  decomposes  during 
evaporation,  into  CaS  and  H2S  ;  the  CaS  is  not  solu- 
ble in  water. 

Ca(SH)2  is  used  by  tanners  to  remove  the  hair 
from  the  hides.  Even  from  the  living  skin  the  hair 
falls  out  when  the  solution  is  repeatedly  applied. 

Calcium  monosulfid,  CaS,  is  best  prepared  in  the 
dry  way.  Mix  gypsum  with  charcoal  powder  in 
the  proportion  of  gypsum  3.6  parts,  charcoal  1  part, 
and  heat  the  mixture  in  a  fireclay  crucible  to  full 
redness  in  a  suitable  furnace  until  the  blue  flame 
stops  burning  at  the  small  opening  left  in  the  lid  of 
the  crucible. 
CaS04.2H20  +  4C  +  red  heat  =  CaS  +  2H20  + 

4CO. 

The  porous  mass  of  CaS  is  white,  when  the  materials 
are  pure.  It  is  mostly  somewhat  reddish-yellow. 
If  exposed  to  the  sunlight  during  the  day  it  will  be 
luminous  during  the  dark  of  the  night.  It  is  a 
phosphorescent  body.  It  is  used  for  faking  ghosts. 
When  mixed  with  water  it  decomposes : 

2CaS  +  2H20  =  Ca(SH)2  +  Ca(HO)2 
The  solutions  of  the  alkaline  sulfids  become  yellow 
after  some  time  of  standing  in  contact  with  the  air. 
This  phenomenon  is  due  to  the  forming  of  poly- 
mlfid  thus  : 

2K2S  +  H20  +  0  =  2K(OH)  +  K2S2,  pot.  disulfid. 

2K2S2  -f  H20  +  0  =  2K(OH)  +  K2S4 

2K2Sn  +  IPO  +  0  =  2K(OH)  -f  K2S2n, 

pot.  polysulfid. 
16 


242  CHEMISTRY    SIMPLIFIED. 

As  the  action  advances  the  color  of  the  liquid 
deepens  until  it  becomes  blood-red  ;  the  capacity  of 
the  potassium  for  sulfur  is  now  satisfied,  (2n  =  9) 
but  the  oxydation  keeps  on,  the  solution  deposits 
sulfur  in  crystals,  the  color  becomes  lighter  until, 
at  last,  a  cloudy  solution  remains  with  the  sulfur 
all  separated  out  in  crystals ;  the  liquid  is  K(OH) 
water  thus : 

2K2S9  +  H20  +  0  =  K2S8  +  2K(OH)  -f  10S. 
Oxydation,  therefore,    means   substitution  of  0  in 
the  place  of  8.     Note. — Write  out  these  reactions  for 
Na2S  and  (NH4)2S. 

ACTION    OF    SULFUR    ON   THE    ALKALINE    HYDROXYDS. 

Bring  flour  of  sulfur  together  with  a  strong  solu- 
tion of  KOH  (1  :  3)  into  a  test-tube.  At  ordinary 
temperature  the  action  is  too  slow  to  be  perceptible. 
On  heating,  the  liquid  assumes  a  yellow  color,  which 
grows  in  intensity  at  the  boiling  heat,  while  the 
sulfur  disappears.  No  gas  is  seen  to  escape,  hence 
the  oxygen  of  the  KOH,  as  well  as  the  hydrogen, 
must  enter  into  the  new  unions.  The  brown-red 
liquid  acts  upon  copper  or  silver  like  K2S  +  H20, 
that  is  to  say,  a  black  sulfid  CuS  or  Ag2S  forms, 
while  K2  unites  with  the  H20  as  2KHO.  Hence 
we  may  assume  that  the  first  action  of  2KHO  upon 
S  gives  K2S  +  H202.  But  the  latter  H202  is 
hydrogen  peroxyd,  a  powerful  oxydizing  agent, 
which  tends  to  transfer  one  0  to  any  oxydizable 
body  in  its  neighborhood,  and  this  is  S.  Now  we 
know  two  oxyds  of  sulfur,  SO2  and  SO3,  either  of 


OTHER  COMPOUNDS  OP  SULFUR.       243 

which  might  form,  but  in  fact  quite  another  com- 
bination results,  namely,  S202,  and  this  oxyd  com- 
bines thus  with  2KHO  to  form  K2(S203).  Evi- 
dently one  can  explain  this  in  another  way  by 
assuming  first  the  forming  of  SO2,  then  of  K2(SO3), 
and  then  the  entering  of  one  S  into  tljis  molecule  in 
presence  of  an  excess  of  KHO  and  of  S  molecules. 
The  final  reaction  presents  itself  in  the  balanced 
equation  : 

mKHO  +  nS  +  water  +  heat=2K2S9+K*(S203)-f- 
3H20  +  water  -f  (m— 6)KHO  -h  (n— 20)S. 

K2S9  is  potassium  polysulfid  (the  maximum  of 
saturation),  K2(S203)  is  potassium  thiosulfate  or 
potassium  hyposulfite. 

If  XaHO  be  taken  instead  of  KHO  the  action 
will  be 

6XaHO  -f  20S  =  2Xa2S9  +  Na2(S203)  +  3H20 

Xa2(S203)-flOH20  easily  crystallizes  in  large,  trans- 
parent, colorless  crystals.  It  is  the  so-called  hypo 
of  the  photographers  because  its  water  solution  dis- 
solves the  insoluble  AgBr  of  the  negative  plate,  but 
not  the  metallic  silver  which  resulted  from  the  ac- 
tion of  the  developing  agent  upon  the  exposed  plate, 
and  therefore  fixes  the  image.  Na2S203  also  dis- 
solves the  insoluble  Pb(S04).  It  is  the  chief  in- 
gredient of  the  extracting  solution  in  the  Russell 
process  for  extracting  the  silver  from  its  ores  ;  hence 
a  most  important  substance. 

Technical  manufacture  of  the  salt.  Boil  together 
NaHO,  S  and  water  until  the  sulfur  is  all  dissolved. 


244  CHEMISTRY    SIMPLIFIED. 

Then  pass  SO2  gas  into  the  liquid  until  the  yellow 
color  has  disappeared  and  allow  the  hot  liquid  to 
cool.  The  hyposulfite  crystallizes.  The  proportions 
are  :  Solid  NaHO  96  parts,  flowers  of  sulfur  64  parts, 
water  500  parts.  The  principle  of  the  action  is  that 
SO2  takes  from  the  polysulfid  one  S,  turning  into 
S202,  and  the  latter  decomposes  2NaHO  to  form 
Na2S203+H20.  Thus: 

Na2S9  +  ISNaOH  +  9S02=9Na2S203+9H20+ 
Na2S,  H20+Na2S  +  S02=Na2(S03)-f-H2S;  2H2S 
+S02=S3-f2H20. 

Ultimately  there  must  be  a  precipitation  of  sulfur 
if  an  excess  of  SO2  is  run  into  the  solution. 

Second  process.  The  raw  material  is  here  the 
waste  product  from  the  Leblanc  soda  process,  which 
is  essentially  a  mixture  of  CaS+CaO.  If  this  waste 
be  exposed  to  the  action  of  air  for  a  proper  period  an 
oxydation  will  set  in,  by  which  calcium  thiosulfate, 
calcium  sulfate  and  sulfur  are  produced.  If  this 
oxydized  material  be  extracted  with  water  the  solu- 
tion contains  chiefly,  Ca(S203),  calcium  thiosulfate. 
On  the  addition  of  Na2C03  we  obtain  a  precipitate 
of  CaCO3  and  a  liquid  holding  Naa(S2O8).  Evapo- 
ration and  crystallization  furnish  commercial  hypo. 

Note.  The  oxyd  SO  or  S202  has  not  yet  been 
obtained  in  the  free  state.  For  as  soon  as  an  acid 
is  added  to  a  solution  of  hypo  there  is  an  action 
thus  :  Na2(S203)+water  +  2HCl=2NaCl+S02+S. 
This  precipitation  of  sulfur,  upon  acidification,  is 
an  excellent  means  for  recognizing  the  presence  of 
a  thiosulfate. 


OTHER    COMPOUNDS    OF    SULFUR.  245 

ACTION    OF   H2S    UPON    THE    SOLUTIONS    OF    METALLIC 
SALTS. 

(1)  Upon  solutions  of  potassium,  sodium,  ammonium 
and  calcium  salts.  We  find  that  no  action  takes 
place. 

K2S04  4-  water  +  H2S  =  K2S04  -f  water  +  H2S 
Na2S04  -f  water  -f  H2S  =  Xa2S04  +  water  -f  H2S 
(NH4)2S04+water  +  H2S  =  (NH4)2S04-{-  water  + 

H2S 

CaSO4  +  water  +  IPS  =  CaSO4  +  water  +  H2S. 
Reasons :  If  there  were  action  it  would  have  to  be 
thus 
,K2S04  +  water  +  H2S  =  K2S  +  H2S04  +  water. 

But  we  have  seen  that:  K2S  +  water  +  H2S04  = 
K2S04  -f  water  +  H2S,  and  similarly  for  other  sul- 
fids  ;  therefore  the  end  equaling  the  beginning,  there 
can  be  no  action. 

(#)    Upon  solutions  of  iron-zinc-aluminum  salts. 
FeSO4  +  water  +  IPS  =  FeSO4  +  water  +  IPS 
FeCl2  -f  water  +  IPS  =  Fed2  +  water  +  H2S 

A12(S04)3  +  water  +  IPS  =  A12(S04)3  +  water  + 

H2S. 

There  is  no  action  for  the  same  reason  as  given  above. 
We  generate  IPS  by  acting  upon  FeS  with  very 
dilute  IPSO4,  hence  IPS  cannot  form  FeS  in  pre- 
sence of  free  acid,  which  must  be  formed  simul- 
taneously with  the  FeS  : 
FeSO4  +  water  -f  IPS  =  FeS  +  water  +  H2SO*. 


246  CHEMISTRY    SIMPLIFIED. 

The  same  is  to  be  said  of  zinc.  But  aluminum  does 
not  combine  with  the  sulfur  in  H2S  under  any 
circumstance,  in  water  solution. 

(3)  Action  of  water  solution  of  K2S,  Na2S,  (NH4)2S 
upon  the  solutions  of  iron,  zinc  and  aluminum  salts. 

There  is  always  a  precipitate  formed,  but  this  is 
not  the  same  thing  for  all  the  three  metals  ;  thus  : 

FeSO4  +  water  +  K2S  =  FeS  +  K2S04  +  water 
FeS  forms  as  a  voluminous  black  precipitate.    Why  ? 
Because  there  is  no  H2S04  formed,  but  K2S04,  and 
K  is  the  most  positive  of  the  metals,  most  difficult 
to  be  displaced  in  its  salts. 

Na2S,(NH4)2S  act  the   same.     Write  the  equa- 
tions. 

ZnSO4  +  K2S  +  water  =  ZnS  +  K2S04  +  water 
ZnS   is  a  white  flocculent  precipitate.     Reason  as 
before. 

Write  equations  for  ZnSO4  +  Na2S,  (NH4)2S. 
A12(S04)3  +  3K2S.+  water  =  2A1(OH)3  + 

3K2S04  +  3H2S 

as  there  is  no  affinity  between  Al  and  S,  the  latter 
must  form  IPS.  Aluminum  hydroxyd  forms  in- 
stead of  the  sulfid. 

(4)  Action  of  H2S  upon  the  solutions  of  lead,  cop- 
per, tin,  mercury,  silver  and  gold  salts.     Here  we  find 
that  precipitation  of  the  sulfids  occurs  whether  the 
solutions   be  neutral  or  whether  they  contain  free 
acid. 

PbS,  a  flocculent,  brownish-black  precipitate  from 
cold  solutions,  a  bluish-grey  from  a  hot  solution. 


OTHER  COMPOUNDS  OF  SULFUR.        247 

CuS,  a  flocculent  brownish-black  precipitate. 

SnS,  a  flocculent  brown  precipitate  from  stannous 
salts. 

SnS2,  a  flocculent  yellow  precipitate  from  stannic 
salts. 

Ag2S,  a  flocculent  black  precipitate. 

Hg2S,  a  flocculent  brown-black  precipitate. 

Au2S3,  a  fine,  granular,  brown  precipitate. 
SAuCl*  +  3H2S  +  12H20  +  heat  =  8Au  +  24HC1 
+  3H2S04. 

This  means  that  the  gold  sulfid  has  very  slight 
stability,  heat  causing  the  metal  to  precipitate.  The 
marked  difference  in  the  action  of  the  metal  solutions 
towards  IPS  will  suggest  at  once  the  utilization  for 
separating  a  mixture  of  salts  by  means  of  IPS. 
Let  a  solution  be  made  up  containing  the  following 
chlorids:  SnCl4,  CuCl2,  HgCl2,  A1C13,  Fed2,  ZnCl2, 
CaCl2,  NaCl  and  KC1.  Let  HC1  be  added  and  then 
IPS  passed  through  it,  the  liquid  being  warm,  but 
not  boiling.  A  precipitate  falls,  being  a  mixture  of 
SnS2,  CuS,  HgS.  When  the  liquid  smells  strongly 
of  IPS  filter  and  call  the  precipitate  of  mixed  sul- 
fids  (A).  The  filtrate  is  then  made  alkaline  with 
XH4OH,  and  another  precipitate  falls,  of  what? 
Of  Al(OH)*,  FeS,  ZnS.  Why?  Because  the  fil- 
trate contains  IPS  in  solution  which  becomes 
(NH4)2S  when  NH4HO  is  added,  and  the  (NH4)2 
acts  upon  the  Al,  Fe,  Zn  salts  as  soon  as  the  free 
HOI  is  neutralized  by  (NH4)HO.  Pass  IPS  into 
the  liquid  in  order  to  make  a  complete  precipitation, 
until  liquid  smells  strongly  of  ammonium  sulfid. 


248  CHEMISTRY    SIMPLIFIED. 

Filter  and  call  this  precipitate  (B).  Into  the  fil- 
trate pass  CO2  gas.  Why  ?  Because  we  know  that 
calcium  carbonate  is  insoluble  in  water,  and  this 
solution  being  alkaline  with  ammonia,  the  CO2  will 
form  (NH4)2C03  and  this  will  give  with  CaCl2, 
CaCO3  plus  (NH4)C1.  Filter.  Name  this  precipi- 
tate (C).  In  filtrate  can  now  be  only  KC1  +  NaCl 
+  NH4C1  +  (NH4)2C03  +  (NH4)2S.  Evaporate 
to  dryness  in  porcelain  dish,  then  heat  over  direct 
flame  until  the  ammonium  salts  have  smoked  away. 
Dissolve  the  residue  (KC1,  NaCl)  in  1  or  2  c.c.  of 
water.  We  have  not  come  across  an  action  by 
which  we  can  well  separate  the  2  alkali  metals  from 
one  another  except  the  difference  in  the  solubility 
of  the  sulfates  and  the  nitrates.  Convert  KC1  + 
NaCl  into  K2S04  +  Na2S04.  How?  By  adding 
a  few  drops  of  H2S04  to  the  1  or  2  c.c.  of  liquid  ; 
by  evaporating  this  liquid  to  dryness  and  by  then 
heating  to  red  heat  until  no  odor  of  H2S04  comes 
off.  Because  we  know  by  experience  the  following 
actions: 

2NaCl  +  H2S04  +  heat  =  Na2SO4  +  3HC1. 
2KC1  +  H2S04  +  heat  =  K2S04  +  2HC1. 
Dissolve  the  residue  in  little  boiling  water  ;  bring 
a  drop  upon  a  piece  of  glass,  let  evaporate  and  ex- 
amine under  the  microscope.     As  the  K2S04  isvery 
much  less  soluble  than  the  Na2S04,  the  former  will 
crystallize  first  from  the  margin  of  the  drops  inward. 
In  the  center  will  be  found  the  long  prismatic  crys- 
tals of  Na2S04,  outside  the  stumpy,  almost  cubic 
crystals  of  K2S04. 


OTHER    COMPOUNDS    OF    SULPHUR.  249 

If  the  nitrate  test  is  to  be  made  the  first  steps 
must  be  the  conversion  of  KC1,  XaCl  into  KXO3, 
XaXO3.  We  remember  that  AgCl  is  insoluble  in 
water  and  dilute  acids,  also  that  metallic  silver  dis- 
solves in  HXO3  of  medium  concentration  forming 
AgNO3.  If  therefore  we  add  the  AgNO3  solution 
to  the  KC1,  XaCl  solutions  so  long''  as  the  white 
cloud  is  forming,  while  stirring,  then  a  change  will 
occur  thus, 

KC1  +  AgNO3  +  water  =  AgCl  -f  KNO8. 
Filtering  off  AgCl,  a  drop  of  the  filtrate  evaporated 
upon  a  glass  slide  will  give  the  characteristic  crys- 
tals of  the  two  niters  if  both  metals  (K,  Xa)  are  pres- 
ent in  the  unknown  substance,  or  the  crystals  of 
either  alone,  as  the  case  may  be.  Since  K  salts  im- 
part to  the  mantle  of  the  gas  flame  a  purple  color, 
and  Xa  salts  an  orange-yellow  color,  properly  ap- 
plied flame  test  may  decide  the  question  of  the  pres- 
ence or  absence  of  either  of  the  two  metals,  but  it  is 
not  here  the  place  to  treat  of  these  phenomena  in 
greater  detail. 

Let  us  now  turn  our  attention  to  the  precipitate 
(A),  and  see  how  far  our  knowledge  will  enable  us 
to  separate  and  recognize  the  metals  which  it  does, 
or  may  contain. 

(a)  HgS.  All  salts  of  mercury  are  volatile  either 
as  a  whole,  or  at  least  the  metal  itself.  If  the  mix- 
ture of  sulfids  includes  HgS,  we  must  get  a  subli- 
mate of  some  kind  by  heating  this  mixture  in  a 
hard-glass  tube,  closed  at  one  end.  Three  inches 
of  the  tube  will  suffice.  (Precipitate  must  be  dried 


250  CHEMISTRY    SIMPLIFIED. 

before  placing  it  in  the  tube).  Heat  closed  end  to 
full'redness  :  The  sulfids  melt,  HgS  sublimes.  When 
tube  has  cooled,  break  off  the  closed  end,  crush  glass 
and  sulfids,  act  upon  with  HNO3,  pick  out  the 
glass  and  evaporate  to  dry  ness,  then  add  water. 

(b)  If  copper  is  present,  a  blue  solution  results,  if 
tin,  a  white,  pulverulent  body  of  SnO2  ;  if  lead,  a 
white  powder  of  PbSO4.     (Why  ?     Because  3PbS+ 
8HN03  ==  3PbS04  +  4H20  +  8NO.) 

Filter  and  wash  the  filter  with  water.  Squirt  the 
white  powder  into  a  small  beaker-glass  and  add  a 
few  grams  of  Na2(S203)  sodium  thiosulfate.  (Hunt 
up  this  body  under  the  action  of  S  upon  KOH, 
NaOH  and  study  its  formation.)  Stir  well  5  to  10 
minutes,  filter.  Na2S203  acts  upon  PbSO4  thus : 

PbSO4  +  2Na2S203  +  water  =  Pb(S203).Na2S203 

+  Na2S04. 

Lead-sodium  thiosulphate  is  soluble  in  water,  hence 
if  you  filter,  the  filtrate  will  contain  the  lead  salt, 
and  if  a  white  residue  be  left  on  the  filter  it  must  be 
SnO2.  Boil  the  filtrate  and  blue-grey  PbS  falls 
out : 

PbS203.Na2S20    +  H20  -f  heat  =  PbS  + 
Na2S04  -f  H20  +  SO2  +  S. 

(c)  Mix  the  filter  ashes  with  the  problematic  SnO2 
together  with  a  little  Na2C03.     Press  mixture  into  a 
cavity  on  a  piece  of  charcoal,  apply  a  good  reducing 
flame  with  a  blow-pipe ;  break  out  the  fused  mass 
with  a  knife-point,  grind  up  in  a  small  mortar  with 
water.     If  white  flakes   with  metallic  lustre  show 


OTHER  COMPOUNDS  OF  SULPHUR.       251 

themselves  after  washing  away  the  charcoal,  then 
the  white  powder  was  surely  tin.  We  have  thus 
proved  the  metals  in  precipitate  (A)  with  no  other 
means  but  such  as  our  progressively  acquired 
knowledge  has  furnished  us. 

Precipitate  (B).  We  have  present,  presumably, 
FeS,  ZnS,  Al(OH)3.  It  was  found  tliat  all  three 
dissolve  in  HC1 : 

FeS  +  2HC1  ==  Fed2  +  H2S. 

ZnS  +  2HC1  =  ZnCl2  +  IPS. 

Al(OH)3  -f  3HC1  =  A1C13  +  3H20. 

By  boiling  solution  with  1  c.c.  HXO3,  we  shall 
convert  FeCl2  into  Fed3,  thus: 

3FeCl2  +  3HC1  +  HNO3  =  3FeCl3  +  2H20  + 
NO,  the  solution  turns  yellow.  NH4(HO)  decom- 
poses Fed3,  A1C13,  thus: 

Fed3  +  3NH4(HO)  ==  Fe(HO)3  -f  3NH4C1. 

A1C13  -f  3NH*(HO)  ==  Al(HO)3  -f-  3NH4C1. 

Fe(HO)3,  a  flocculent,  brmvn  substance,  insoluble 
in  water  and  NH4HO.  But  ZnCl2  behaves  differ- 
ently towards  NH4HO  ;  it  gives  first  a  white  floccu- 
lent precipitate,  but  on  adding  more  XH4HO  the 
precipitate  dissolves. 

ZnCl2  +  2NH4HO  =  Zn(HO)2  +  2NH4C1. 

Zn(HO)2  -f  2NH4HO  =  Zn(NH40)2  +  2H2O, 
soluble  in  water  and  XH4(HO).  Hence  it  follows 
that  we  can  separate  Zn  from  Fe  +  Al  by  means  of 
NH4HO.  Add  NH4HO  to  the  hot  liquid  and  stir 
until  it  smells  strongly  of  NH4HO ;  then,  filter. 


252  CHEMISTRY    SIMPLIFIED. 

Into  filtrate  pass  IPS  and  white  ZnS  falls.  Why? 
Make  answer  yourself  from  what  was  given  above. 
The  forming  of  a  white  precipitate  proves  the 
presence  of  zinc.  Wash  the  precipitate  from  NH4HO 
from  filter  into  a  beaker  glass  or  porcelain  dish, 
add  Na(HO),  a  couple  of  grains,  and  boil.  Fe(HO)3 
is  insoluble  in  Na(HO) ;  Al(HO)3  is  soluble  in 
Na(HO),  because  it  combines  with  the  latter  to  make 
soluble  sodium  aluminate. 

Al(HO)3  +  3Na(HO)  =  AlNa303  -f  3H20 
Filter.     To  prove  Al   in  the  filtrate,  acidify  with 
HC1  and  then  add  NH4HO.     If  a  white,  flocculent 
precipitate  falls,  aluminum  is  present.     Thus  : 

Al(NaO)3  -f-  3HC1  =  A1C13  +  3NaCl  both  soluble. 
A1C13  -f  3NH4HO  =  Al(HO)3(insoluble)+3NH4CL 
To  prove  that  the  brown  substance  is  iron  hydroxyd, 
dry  it  on  a  filter.  Put  some  of  the  dry  mass  in  a 
cavity  on  charcoal  and  heat  in  a  reducing  (yellow) 
flame  with  blowpipe  ;  then  test  the  mass  with  a 
magnet.  If  the  substance  clings  to  magnet  the 
presence  of  iron  is  proved.  Why  ?  Because  by  the 
reducing  flame  the  trioxyd  Fe203  is  changed  either 
to  metallic  iron,  or  to  the  tetroxyd  Fcz  O4  and  both 
are  magnetic.  Thus : 

Fe203  -f-  3C  +  red  heat  =  Fe2  +  3CO 

3Fe203  +  C  +  red  heat  =  2Fe304  +  CO 

Precipitate   (C).      The    white    substance    thrown 

down. by  (NH4)2C03  can  only  be  CaCO3  according 

to  our  present  state  of  knowledge.     Later  on  we  will 

learn  of  several  more  elements   whose  carbonates 


OTHER  COMPOUNDS  OF  SULPHUR.       253 

will  fall  with  the  calcium.  But  to  prove  the  sub- 
stance absolutely,  ignite  it  with  the  soda  at  yellow 
heat.  Then  moisten  with  1  or  2  drops  of  water. 
If  calcium  oxyd,  it  will  slake,  i.  e.  get  warm  and 
swell  up  a  little.  If  it  does,  add  a  few  drops  of  very 
dilute  H2S04  and  heat,  it  will  all  dissolve;  then 
allow  one  drop  of  liquid  to  evaporate  on  a  glass 
slide,  and  examine  the  crystals  under  a  microscope. 
They  will  be  the  characteristic  needle-shaped  or 
arrow-head  shaped  twins  of  CaSO4. 

Thus  our  analysis  is  finished.  It  was  introduced 
at  this  point  to  show  you  that  analytical  chemistry 
simply  means  the  thinking  application  of  the  chem- 
ical knowledge  which  we  gradually  accumulate  by 
experiment. 

SOME  OTHER  SULFUR  COMPOUNDS. 

Hydrogen  persulfid,  H2S2.  Whenever  you  acidify 
a  solution  of  ammonium,  sodium,  or  potassium  sul- 
fid  and  then  boil  the  solution,  there  will  be  at  first 
only  the  odor  of  H2S.  But  in  measure  as  this  odor 
becomes  less  pronounced,  there  will  appear  another 
odor,  pungent  and  offensive,  somewhat  resembling 
the  odor  of  fresh  onions.  As  the  eyes  begin  to 
smart  if  you  peel  and  cut  up  an  onion,  so  will  the 
eyes  become  affected  if  exposed  to  the  fumes  arising 
from  the  above  boiling  solution.  This  odor  is  due 
to  H2S2.  This  latter  body  is  at  ordinary  tempera- 
ture a  yellow  liquid,  little  soluble  in  water,  and 
therefore  separating  from  water  in  small  oily  drops. 
Preparation  :  Pour  yellow  Na2S  or  (NH4)2S  into  an 


254  CHEMISTRY    SIMPLIFIED. 

excess  of  dilute  HC1  or  H2S04  and  let  the  milky 
liquid  stand  for  some  hours.  Then  pour  off  the 
liquid  and  you  will  find  this  yellow,  evil-smelling 
substance  at  the  bottom.  There  is  no  technical  use 
for  it  at  present. 

Sulfur  and  chlorine,  SCI.  Place  flowers  of  sulfur 
(2  grams)  in  a  small  tubulated  retort  and  conduct 
dry  chlorine  gas  into  the  retort.  The  chlorine  is 
eagerly  absorbed,  generating  heat,  which  must  be 
removed  by  cold  water  on  the  outside.  A  red  liquid 
forms.  When  the  sulfur  has  all  disappeared,  close 
the  tubulus  of  the  retort  and  let  the  neck  of  the  re- 
tort project  into  a  receiver,  cooled  by  hydrant  water. 
Then  heat  the  retort.  A  yellow-red  liquid  con- 
denses in  the  receiver  and  finally  sulfur  remains  in 
the  retort.  The  original  liquid  was  therefore  a  so- 
lution of  sulfur  in  sulfur  chlorid.  The  latter  has 
specific  gravity  of  1.68.  It  fumes  at  the  air  because 
the  air-moisture  decomposes  it : 

4SC1  +  2H20  ==  4HC1  +  3S  +  SO2. 
The  one  property  which  makes  this  sulfur  chlorid 
technically  valuable  is  its  solvent  power  for  sulfur. 
100  SCI  dissolve  73  S.  If  soft  india  rubber  is  placed 
in  this  solution  of  sulfur  in  SCI,  the  rubber  will  ab- 
sorb sulfur  and  become  vulcanized.  There  are  other 
combinations  of  S  -j-  Cl  and  S  -f-  Cl  +  0,  but  of  no 
practical  interest. 

Sulfur  and  carbon,  CS2.  Vapors  of  sulfur  com- 
bine with  carbon  at  a  red  heat  forming  a  vaporous 
compound  CS2,  carbon  disulfid.  On  a  large  scale 
the  substance  is  made  in  vertical  retorts  of  cast-iron 


OTHER    COMPOUNDS    OF    SULPHUR.  255 

lined  with  fire  clay.  The  retorts  are  filled  with 
small  bits  of  charcoal  and  stand  walled  in  so  that 
they  may  be  brought  to  red  heat.  The  sulfur  is  in- 
troduced through  an  inclined  tube  at  the  bottom  of 
the  retort.  The  vapors  of  CS2  are  condensed  against 
cold  water.  CS2  sinks  to  bottom  of  eondenser  and 
can  be  drawn  off.  The  first  or  raw  product  is  far 
from  pure  and  has  a  most  offensive  odor.  By  redis- 
tillation and  shaking  with  metal  chips  as  lead,  cop- 
per or  mercury,  a  colorless  liquid  is  obtained  whose 
odor  is  rather  agreeable.  In  1840  one  pound  of 
CS2  was  worth  §5.00  ;  in  1860  only  5  cents  ;  to  such 
an  extent  had  the  process  been  improved. 

Properties.  CS2  is  a  very  mobile  liquid.  Sp.  G. 
=  1.268.  Boils  at  46°  C.  High  index  of  refrac- 
tion. Very  inflammable,  burns  with,  bluish-white 
flame.  When  a  current  of  air  blows  through  the 
liquid  CS2,  soon  snowy  crystals  form  on  the  glass 
(CS2.H20);  the  temperature  falls  to  -18°  C.;  water 
dropped  on  the  liquid  freezes  instantly.  CS2  easily 
dissolves  animal  and  vegetable  fats  and  oils,  and  it 
dissolves  sulfur.  Upon  these  facts  are  based  the 
technical  applications  of  carbon  disulfid.  (1).  To 
extract  the  sulfur  from  the  sulfur  earth,  where  the 
latter  is  abundant  (near  active  or  near  extinct  vol- 
canoes). (2).  To  extract  the  fat  from  bones  (glue 
factories,  stock-yard  slaughter-houses).  (3).  To  ex- 
tract the  oil  from  the  seeds  (cotton,  flax,  rape, 
poppy,  olive,  nut)  more  thoroughly  than  can  be 
done  by  mere  pressing  of  the  crushed  seeds.  (4). 
To  remove  fat  from  raw  wool ;  from  woolen  cloth 


256  CHEMISTRY    SIMPLIFIED. 

after  dyeing  with  certain  colors.  In  all  of  these 
processes  much  care  must  be  exercised  on  account 
of  the  inflammability  and  the  poisonous  effects  of  the 
carbon  disulfid.  It  produces  first  headache,  drowsi- 
ness, stupefaction ;  if  inhaled  for  a  long  time,  death. 


CHAPTER  XV. 

CARBON  COMPOUNDS ;  ORGANIC  BODIES. 

WE  discovered  in  the  lime  gas  the  oxyd  of  a 
peculiar  element  which  we  named  carbon  from  its 
resemblance  and  action  to  charcoal.  As  element 
we  find  carbon  among  minerals  in  two  forms :  as 
diamond  and  as  graphite.  Diamond  is  the  hardest, 
graphite  the  softest  of  all  minerals.  Both  resist  all 
agents  with  energy.  A  yellow  heat  is  required  to 
enable  oxygen  to  combine  with  adamantine  carbon 
as  well  as  with  graphite  carbon.  It  was  a  great 
feat  to  even  suspect  that  diamond  was  merely  crys- 
tallized carbon.  Isaac  Newton  concluded  that  dia- 
mond must  be  a  combustible  substance,  on  account 
of  its  high  index  of  refraction.  The  Academy 
of  Florence  in  1694  showed  by  experiment  that 
diamond  disappears  in  the  focus  of  a  large  lens. 
Lavoisier  showed,  in  1736,  that  lime  gas  results  from 
the  burning  of  diamond,  and  Humphrey  Davy,  in 
1807,  proved  it  to  be  pure  carbon.  No  attempt  at 
making  diamond  artificially  has  been  a  success,  up 
to  this  time,  and  it  is  not  known  by  what  way 
Nature  arrives  at  the  product.  That  diamond  has 
been  found  in  meteoric  iron  together  with  amor- 
phous carbon  (Koenig,  1889)  indicates  a  high  tem- 
perature as  one  of  the  conditions.  On  the  other 
17  ( 257 ) 


258  CHEMISTRY    SIMPLIFIED. 

hand  the  perfect  crystals  found  in  flexible  sandstone 
in  Brazil  indicate  a  low  temperature  as  one  of  the 
conditions. 

Graphite  is  of  very  common  occurrence  in  the 
archean  rocks  either  in  mica  schist  or  in  white  crys- 
talline limestone.  Sometimes  large  bunches  to- 
gether, but  mostly  in  isolated  scales.  Graphite 
forms  in  pig-iron,  also  in  gas  retorts  at  high  heat. 
It  burns  more  readily  than  diamond,  especially  in 
oxygen  gas.  Long  boiling  with  fuming  HNO3  con- 
verts it  into  a  yellow  substance  which  has  been 
named  graphitic  acid. 

The  mineral  coal  cannot  correctly  be  named 
carbon,  not  even  the  finest  anthracite  of  Pennsyl- 
vania ;  it  contains  however  up  to  95  per  cent,  of 
carbon.  The  great  storage  of  carbon  in  the  earth 
must  be  looked  for  in  the  limestones ;  and  in  the 
air,  though  the  percentage  of  carbon  dioxyd  in  the 
atmosphere  be  but  0.02  per  cent.  Yet  all  this  im- 
mense quantity  of  carbon  is  of  very  little  value  to 
mankind.  As  CO2  it  is  equivalent  to  spent  energy, 
to  an  uncoiled  spring.  At  this  point  intervenes 
organic  life  contained  in  the  animated  cell  filled  with 
that  most  mysterious  substance,  the  protoplasm. 
Under  its  influence  carbon  dioxyd  is  split  up  into 
carbon  and  oxygen,  a  part  of  the  oxygen  returns  to 
the  air,  the  remainder  together  with  carbon  and 
hydrogen  serving  in  building  up  the  body  of  the 
plants. 


CARBON    COMPOUNDS.  259 

THE    COMBINATIONS    OF    CARBON    AND    OXYGEN. 

We  saw  that  the  limestone  gas  is  an  oxyd  of  car- 
bon, and  furthermore  that  this  oxyd  changes  into  a 
combustible  oxyd  by  the  action  of  zinc  and  heat. 
There  are  then  two  oxyds  of  very  differing  proper- 
ties. Being  now  in  possession  of  the  required  knowl- 
edge we  will  proceed  to  the  properties  and  composi- 
tion of  these  oxyds. 

Carbon  dioxyd,  CO2,  often  erroneously  named 
carbonic  add.  This  is  our  limestone  gas  as  well  as 
the  gas  evolved  from  all  carbonates  by  the  addition 
of  HC1  or  any  other  so-called  acid.  This  is  a  sub- 
stance of  fundamental  importance,  and  its  proper- 
ties should  be  memorized  by  any  engineer,  because 
what  is  called  perfect  or  complete  combustion  means 
nothing  but  the  conversion  by  burning  of  carbon 
into  CO2,  and  because  by  this  combustion  the  high- 
est heat-value  is  obtained  from  coal  or  any  other 
fuel. 

Physical  properties.  Carbon  dioxyd  is  a  colorless 
gas  without  odor ;  but  it  gives  to  water  a  pleasant, 
prickling  taste.  Its  specific  gravity  is  1.524,  hence 
the  gas  is  found  near  the  floor  when  it  issues  into, 
the  workings  of  a  tunnel,  shaft,  or  other  mine-work- 
ing, or  in  caves  such  as  the  dog-cave,  where  a  dog 
dies  rapidly,  while  a  standing  man,  alongside, 
breathes  freely.  It  spec,  heat  is  0.22  (water  =1), 
1  liter  at  0°  C.  weighs  1.97  grams.  The  gas  can  be 
liquefied  at  the  freezing-point  of  water  under  a 
pressure  of  38.5  atmospheres ;  at  31°  C.  a  pressure  of 
74  atmospheres  is  required.  If  two  strong  metallic 


260  CHEMISTRY    SIMPLIFIED. 

vessels  (cylinders)  be  connected  by  a  flexible 
metallic  tube,  and  if  one  vessel  has  been  previously 
charged  with  sodium-hydrogen  carbonate  and  sul- 
furic  acid  in  such  a  way  that  the  agents  only  come 
together  when  the  cylinder  is  tilted,  then  pure 
CO2  will  be  generated,  and  not  being  able  to  escape, 
it  will  liquefy  in  the  second  cylinder  under  its  own 
pressure.  The  temperature  rises  to  40°  C.,  so  that 
upon  screwing  a  metallic  receiver  upon  the  second 
vessel,  the  liquid  CO2  will  distill  into  the  receiver 
and  the  temperature  will  drop  quickly  to  about 
-80°  C.  and  solidify  into  white  crystal-flakes  like 
snow.  (Application  as  a  very  intense  freezing  mix- 
ture.) Liquid  CO2  is  colorless  and  mobile,  its 
specific  gravity  at  ordinary  temperature  being  nearly 
that  of  water.  CO2  is  quite  soluble  in  water  at 
ordinary  temperature,  and  much  more  so  under 
pressure.  The  sparkling  or  boiling  cold-springs,  as 
well  as  the  artificial  soda-water  are  charged  with 
the  gas  under  pressure  and  release  it  when  the 
pressure  is  taken  off.  If  air  be  mixed  with  4  vol. 
per  cent,  of  CO2  it  becomes  unfit  for  the  proper 
oxygenation  of  the  blood  in  the  lungs.  In  larger 
proportion  it  suffocates  at  once.  Note  ventilation  of 
rooms  and  mines  on  this  account.  The  poisonous 
action  is  negative. 

Chemical  properties.  Moist  litmus  paper  will  turn 
to  a  reddish-purple  in  a  test-tube  which  has  been 
filled  with  the  gas.  We  assume  (without  proof) 
that  the  water-solution  contains  a  weak  acid 
H2O.C02  =  H2(C03).  The  gas  is  eagerly  absorbed 


CARBON    COMPOUNDS.  261 

by  NaHO,  KHO,  Ca(HO)2,  NH*(HO)  and  even  by 
Na2CO3  which  changes  into  2NaH(C03).  These 
latter  actions  we  utilize  for  the  identification  of  the 
gas,  for  its  abstraction  from  a  mixture  of  gases  in 
gas  analysis.  Because  if  the  white  precipitate  of 
Ca(C08)  be  filtered  off  and  then  be  acted  upon  by 
dilute  HC1  solution,  a  colorless  and  odorless  gas  will 
be  evolved  which  can  only  be  CO2,  for  SO2  and 
N2O3  are  each  pungently  odoriferous. 

Composition  of  CO2.  If  a  piece  of  purest  charcoal 
be  placed  in  a  knee-tube  over  mercury  (see  proof 
of  SO2),  the  tube  be  partly  filled  with  pure  oxygen, 
and  the  coal  heated  to  redness  it  will  burn  with  a 
bright  light.  When  the  temperature  has  returned 
to  normal  the  volume  of  gas  is  unchanged.  Hence 
1  volume  CO2  contains  1  volume  0. 

But  1  volume  CO2  weighs  1.965  grams. 
1  volume  0  weighs       1.429  grams. 


0.536  grains. 

hence  0.536  is  the  weight  of  carbon  which  has  en- 
tered into  combination.  We  know  that  the  gas  is 
CO2  for  it  is  completely  absorbed  by  introducing  a 
drop  of  NaHO  solution.  Unfortunately  carbon  is 
practically  non-volatile  at  feasible  temperatures, 
hence  we  are  ignorant  of  the  weight  of  one  volume 
of  this  element.  But  since  CO2  and  SO2  are  in 
many  ways  similar  and  because  we  did  prove  in  the 
case  of  SO2  that  the  difference  between  the  weights 
of  equal  volumes  of  SO2  and  oxygen  is  equal  to  J 
volume  of  sulfur,  therefore  we  can  assume  that  0.536 


262  CHEMISTRY    SIMPLIFIED. 

equals  the  weight  of  J  volume  of  carbon,  and  hence 
our  gas  contains  in  one  volume 

1  vol.  0  +  i  vol.  C,  and 
2  vols.  CO2  =  2  vols.  0  +  1  vol.  C 
a  contraction  of  3  to  2. 

On  the  other  hand  it  has  been  found  by  burning 
a  known  weight  of  diamond,  that  1  gram  of  the 
latter  (pure  carbon)  yields  3.666  grams  of  CO2, 
therefore  in  it  are  combined  C  1.00  with  0  =  2,660. 
Having  previously  found  that  the  volume  ratio  is 
CO2  we  arrive  now  at  the  atomic  weight  of  carbon, 

2,666         1  1 

!  by  the  proportion  ^^  =-  £  or  C    =  g-gggj  = 

12.003.  The  atomic  iveight  of  carbon  is  12.  The 
weight  of  1  volume  carbon  vapor  is  1,072.  The 
molecular  weight  of  CO2  =  44. 

Carbon  monoxyd,  CO,  sometimes  called  carbonous 
oxyd.  This  gas  may  be  generated  in  numerous  ways 
of  which  the  most  ordinary  is  the  passing  of  dry  CO2 
over  well  ignited  charcoal  at  a  red  heat.  Use  the 
apparatus  given  under  lime  gas,  substituting  the 
charcoal  for  the  zinc.  Let  the  resulting  gas  pass 
through  solution  of  NaHO  which  will  absorb  any 
CO2  that  may  have  escaped  decomposition.  It  will 
be  seen  that  for  every  bubble  of  CO2  passing  into 
the  charcoal,  there  will  be  two  bubbles  of  carbon 
monoxyd  coming  out. 

1  vol.  CO2  +  C  =  2  vols.  CO. 

This  gas  always  generates  when  any  fuel  burns  im- 
perfectly, that  is  when  there  is  a  lack  of  oxygen. 


CARBON    COMPOUNDS.  263 

If  you  observe  an  anthracite  stove  fire  sometime 
after  fresh  coal  has  been  added  (opening  the  charg- 
ing door)  you  will  see  blue  flames  bursting  out  all 
over  the  coal.  This  is  very  characteristic  of  CO — 
that  is  CO  +  0  +  heat  =  CO2  with  blue  flame. 
Carbon  monoxyd  explodes  with  J  volume  of  oxygen 
or  2  j  volumes  of  air.  It  can  therefore  be  used  in 
gas  engines. 

The  gas  is  neutral,  has  a  gravity  of  0.967,  is  only 
liquefiable  at  — 139°  C.  and  a  pressure  of  35.5  atmos- 
pheres. It  freezes  at  — 207°  C.  It  is  little  soluble  in 
water.  It  is  very  poisonous  in  a  positive  way  inas- 
much as  it  combines  with  the  red  corpuscles  of  the 
blood,  changing  the  color  to  purplish.  As  such  it  is 
the  worst  enemy  to  the  rescuing  parties  who  enter  a 
coal  mine  after  an  explosion,  since  the  combustion 
is  usually  imperfect  and  the  gas  has  nearly  the 
same  gravity  as  air.  The  charcoal  poisoning  is  due 
to  this  gas;  or,  any  boiler-room  may  become  deadly 
from  it  if  the  draft  should  stop  on  reverse ;  its  pres- 
ence cannot  be  told  by  the  odor.  CO  is  quite 
eagerly  absorbed  by  solutions  of  cuprous  chlorid 
Cu2Cl2  either  in  HC1  or  in  NH4.HO.  (Use  in  gas- 
analysis.) 

Proof  that  composition  i$  CO.  Bring  into  a  eudio- 
meter over  mercury  1  volume  of  the  gas  +  J  vol- 
ume of  O  and  explode.  There  will  be  left  1  volume 
of  CO2,  it  follows  that  1  volume  of  CO  contains  the 
same  volume  of  carbon  as  1  volume  of  CO2.  But 
we  saw  above  that  1  volume  of  CO2  contains  1  vol- 
ume of  O,  hence  1  volume  CO  contains  J  volume  of 
C  +  |  volume  of  O. 


264 


CHEMISTRY    SIMPLIFIED. 


STRUCTURE    OF    PLANTS. 

The  structural  unit  of  the  plant  is  the  cell.  The 
natural  shape  of  a  plant  or  animal  cell  is  the 
sphere,  A  (Fig.  74).  When  cells  crowd  each  other 
in  an  aggregate,  their  shape  becomes  polyhedral, 
C  (Fig.  74).  When  crowded  only  in  one  direction 
the  cell  is  apt  to  become  an  elongated  bag — cotton 
or  linen  fiber,  B  (Fig.  74).  Each  live  cell  has  three 

r  FIG.  74. 


B 


essential  parts :  The  cell  wall,  A2,  the  nucleus,  Al, 
the  sap  or  protoplasm,  AS,  filling  the  cell  space. 
From  80  to  90  per  cent,  of  the  sap  is  merely  water. 
The  substance  of  the  cell  wall  is  named  cellulose. 
Since  the  body  of  the  plant  is  made  up  of  root,  stem, 
branches,  leaves,  the  flowers  being  merely  modi- 
fied leaves,  and  since  all  these  are  made  up  either 


CARBON    COMPOUNDS.  265 

of  live  or  dead  cells,  it  follows  that  a  plant,  after 
the  sap  is  dried  out,  is  practically  nothing  but  cel- 
lulose, with  more  or  less  secondary  substances,  such 
as  starch,  coloring  matter,  resin,  which  had  been 
dissolved  in  the  sap  or  had  exuded  from  the  cells 
into  the  intercellular  space.  Wood  is  impure 
cellulose.  The  purest  form  of  cellulose  is  cotton, 
pith,  paper  pulp.  Cellulose  enters  into  so  many 
applications,  and  forms  as  wood  one  of  the  engi- 
neer's sources  of  fuel,  that  we  must  devote  some 
time  and  exertion  to  its  study. 

Let  some  cotton,  or  filter  paper,  be  dried  at  105° 
C.  in  an  air-bath  until  its  weight  shall  have  become 
constant.  We  need  not  try  whether  it  will  burn ; 
we  know  it  will.  But  let  us  contrive  to  burn  it 
completely  in  such  a  way  that  the  products  of  the 
combustion  can  be  collected  and  weighed.  The  pro- 
ducts of  the  burning  are  flame  and  ashes.  Flame  is 
a  mixture  of  gases.  These  gases  we  must  collect. 
We  do  this  first  so  that  we  may  study  the  kinds 
(qualitative)  of  elements  in  the  gases,  and  then, 
in  a  more  guarded  experiment,  the  quantities. 

(1).  We  burn  1  gram  in  a  crucible.  A  very  small 
quantity  of  ashes  remains.  The  ashes  partly  soluble 
in  a  little  water,  show  alkaline  reaction,  and  effer- 
vesce with  HC1 — (K2C03).  This  potassium  carbon- 
ate was  not  originally  in  the  sap ;  the  potassium 
was  combined  with  the  carbon  acids,  which  we  will 
consider  hereafter.  Combustion  converts  these  salts 
into  the  carbonate. 

(2).  We  burn  1  gram  in  an  open  tube  and  draw 


266  CHEMISTRY    SIMPLIFIED. 

(by  means  of  an  aspirator)  the  gases  through  water. 
The  latter  does  not  acquire  acid  reaction,  hence 
sulfur  and  chlorine  are  not  contained  in  the  cellu- 
lose. While  the  substance  burns  we  note  the  de- 
posit of  water  in  the  cool  end  of  the  tube,  therefore 
the  cellulose  contains  hydrogen.  We  draw  a  part  of 
the  burning  gases  through  a  tube  filled  with  lime 
water  and  note  a  strong  white  turbidity  appearing 
showing  the  presence  of  carbon  in  the  cellulose. 

(3).  We  mix  a  gram  of  the  substance  with  soda- 
lime  (CaC03-f  2Na(HO))  and  heat  in  a  tube  closed  at 
one  end — no  smell  si  ammonia  is  noticed.  Moist,  red 
litmus  held  into  the  open  end  does  not  turn  blue, 
hence  nitrogen  is  absent,  and  thus  we  have  proved 
that  cellulose  consists  merely  of  Cm,  Hn,  O. 

And  now  we  proceed  to  find  the  numerical  values 
of  m,  n  and  p.  By  experiment  we  know  that  when 
hydrogen  passes  over  CuO  at  red  heat  H20  will  be 
formed  and  metallic  copper.  Similarly  CuO  heated 
with  charcoal  will  give  metallic  copper  -f-  CO. 
And  if  CO  be  passed  at  red  heat  over  CuO  it  will 
give  Cu  +  CO2.  Upon  these  facts  we  can  now  con- 
trive a  process  and  suitable  apparatus  for  the  pur- 
pose in  hand. 

In  Fig.  75  the  hard,  infusible  glass  tube  T,  20 
inches  long,  f  inch  wide,  is  furnished  with  per- 
forated stoppers,  and  is  placed  into  the  sheet-iron 
charcoal  furnace  F,  being  supported  the  entire  length 
by  a  half  cylinder  of  iron,  thus  preventing  sagging 
and  deformation.  The  tube  is  charged  at  1  with  3 
inches  of  coarse  copper  oxyd,  then  comes  10  inches 


CARBON    COMPOUNDS.  267 

of  copper  oxyd  with  which  has  been  intimately 
mixed  the  cellulose  (0.5  gram  cut  up  with  scis- 
sors). Then  comes  at  3t  5  to  6  inches  of  coiled 
copper  gauze,  which  has  been  partly  converted 
into  CuO  by  heat  and  oxygen.  Everything  must 

FIG.  75. 


be  thoroughly  dried  before  charging,  as  we  de- 
sire to  catch  and  weigh  the  water  formed  by  the 
combustion.  Into  the  stopper  5  fits  the  bulb-tube 
C,  filled  with  pieces  of  CaCl2.  To  this  tube  is 
joined  by  a  short  rubber  connection  the  bulb-tube 
P,  known  as  a  Liebig  potash  bulb,  and  to  this  is 
joined  a  second  smaller  bulb-tube  C'  filled  with 
CaCP.  Through  stopper  4-  passes  the  inlet  tube 
with  rubber  tube  and  spring  clamp  6.  The  rubber 
tube  leads  to  a  holder  for  air  with  tubes  for  drying 
and  purifying  the  air.  The  tubes  are  filled  with 
Na(HO)  in  pieces  to  retain  CO2,  which  is  always 
in  the  air,  and  CaCl2  to  take  up  the  moisture. 
The  bulb  P  is  partly  filled  with  a  1:3  solution  of 
NaHO  in  water.  First  we  weigh  the  tube  C  by 
itself,  and  P-f  C'  together.  During  the  process  of 
weighing,  the  tubes  C,  P,  C'  are  air-tightly  closed 
by  means  of  pieces  of  rubber  and  glass  rod.  Let 
the  weight  of  C=  a  grams,  the  weight  of  P  +  C'  == 


268  CHEMISTRY    SIMPLIFIED. 

b  grams.  After  all  is  again  joined,  open  the  clamp 
6,  so  that  bubbles  will  be  seen  to  rise  in  the  liquid 
of  P;  the  level  in  the  farther  bulb  will  rise  until 
the  bubbles  can  pass  from  the  middle  bulb  through 
the  joining  neck.  The  bubbles  should  pass  at  the 
rate  of  one  per  second.  Now  we  place  a  sheet-iron 
diaphragm  in  the  furnace,  astride  the  tube  2,  just 
where  the  copper  gauze  begins,  heap  in  first  some 
ignited  pieces  of  charcoal,  then  black  pieces,  and 
help  the  fire  by  gentle  fanning.  When  the  tube 
and  gauze  are  red  hot  remove  the  shield  or  dia- 
phragm 2  inches  to  the  left,  and  even  up  the  coal. 
Every  10  minutes  move  the  shield  2  inches  further 
to  the  left,  until  we  have  reached  the  left  end  of  the 
furnace,  and  then  keep  up  a  uniform  red  heat  for 
10  minutes  more.  The  cellulose  is  burnt  up  by 
this  time,  and  the  products  of  the  combustion  have 
been  carried  forward  into  the  absorption  tubes  by 
the  slow  current  of  air.  It  may  be  that  a  small 
quantity  of  water  still  lingers  this  side  of  C.  We 
draw  T  to  the  right  to  heat  the  end  of  it  and  cause 
the  water  to  evaporate  and  to  get  into  C.  Now  we 
detach  first  P  from  (7,  put  on  the  glass  plugs,  then 
draw  out  C  and  put  on  the  plug.  Then  we  weigh. 
The  weight  of  C  will  now  be  a'  grams,  that  of  P  +  C' 
=  bf  grams ;  the  increase  in  C  being  due  to  water, 
the  increase  in  P  +  C'  being  due  to  carbon  dioxyd. 
Having  started  with  0.5  gram  of  cellulose 

a'  _  a  will  be  0.2772  IPO 
b'  — b  will  be  0.8147  CO3 


CARBON    COMPOUNDS.  269 

TT2  1  TT2H 

H2=_        ;  hence  0.2772  H20  = 


H2O      9'  9 

0.0308  H 

c& = n ;  c  =  n  c°2 ;  hence  °-8147  c°2  = 

0.2222  C 
0.5  gr.  cellulose  contains  0.2222  C ;'  0.0308  H  ; 

0.2470  0. 

For  the  difference  0.5  —  0.2222  —  0.0308  =  0.2470 
must  be  oxygen,  we  have  proved  by  the  experi- 
ments above,  that  cellulose  can  contain  only  C,  H, 
0.  Expressed  in  percentage  we  get 

C  =  44.44 

H  -      6.16 

0  —  49.45 

Dividing  these  percentages  by  the  atomic  weights 
we  obtain  the  atomic  quotients  thus, 
44.44 


12 
6.16 


=  3.7033 
-  6.1600 


1 

49.45 

-jg-  =  3.0906 

We  reduce  these  to  units  of  oxygen,  because  oxygen 
has  the  smallest  quotient, 
3.7033 


3.0906 
6.1600 
3^906 
3.0906 
3.0906 


=  1.198  or  1.20 
=  1.993  or  2.00 
=  1.000  or  1.00 


270  CHEMISTRY    SIMPLIFIED. 

and  obtain  the  nearest  whole  numbers  which  are 
12  —  20  —  10.     But  these  numbers  are  divisible  by 
2,  therefore  in  the  molecule  of  cellulose  the  three 
elements  are  contained  in  the  ratio 
C6Hio05  =  cellulose 

The  weight  of  the  molecule  is  6  X  12  +  10  X  1  + 
5  X  16=162 

The  first  point  striking  our  attention  is  that  hydro- 
gen and  oxygen  are  in  this  molecule  exactly  in  the 
same  ratio  as  that  of  water,  so  that  we  might  write 
the  formula  C6(H20)5,  a  hydrate  of  carbon.  As  there 
are  a  number  of  other  bodies  of  this  type  it  is  well 
to  distinguish  them  as  a  group  by  the  name  carbon 
hydrates,  although  '  we  know  well  that  H  -f  0  are 
not  grouped  in  the  molecule  as  H20.  For  if  they 
were,  the  cellulose  would  have  to  part,  on  heating, 
into  C  -f  H2O,  but  it  does  so  only  in  part  as  we 
shall  see  presently  in  the  destructive  distillation  of 
wood. 

Some  of  the  Properties  of  Cellulose  or  Wood  Fiber. 

It  is  colorless  or  white.  It  is  insoluble  in  water, 
in  alcohol,  in  ether,  whether  cold  or  boiling.  It  is 
not  affected  by  dilute  solutions  of  the  alkalies  and 
acids  at  ordinary  temperatures.  Persistent  boiling 
with  these  dilute  agents  slowly  dissolves  it. 

Vegetable  parchment  =  papyrine,  results  when  good 
filter  paper  is  immersed  for  a  few  seconds  into  a 
mixture  of  1  vol.  cone.  H2S04  +  J  vol.  water. 
After  withdrawing  the  paper  from  the  acid  it  must 


CARBON    COMPOUNDS.  271 

be  washed  out  with  much  water  and  finally  with 
a  2  per  cent,  solution  of  ammonium  hydrate,  to  re- 
move every  trace  of  adhering  acid.  It  is  then  dried. 
After  drying,  water  has  little  effect  upon  it ;  it  does 
not  blot,  and  resembles  dried  skin. 

Nitro-cellulose,  gun-cotton,  C6H\N02)3  O5,  tri-nitro- 
cellulose.  Let  cleansed,  dry  cotton  be' immersed  for 
5  minutes  in  a  liquid  consisting  of  1  vol.  fuming 
HNO3  +  3  vols.  cone.  H2S04.  Let  it  then  be 
squeezed  out  and  thrown  into  much  cold  water  and 
washed  until  all  acid  reaction  has  disappeared.  On 
drying  we  find  that  externally  the  cotton  has  re- 
tained shape,  color  and  cell  structure;  its  weight 
has  increased  50  per  cent.,  its  tensile  strength  has 
considerably  decreased.  But  it  has  acquired  the 
faculty  to  explode  with  great  force,  wrhen  struck 
a  sharp  blow  with  a  hammer  upon  an  anvil.  Ignited 
by  a  match  it  burns  instantly  with  a  flash  but  with- 
out detonation.  If  the  material  be  put  into  a  closed 
space,  such  as  a  drill  hole,  and  then  ignited  it  will 
rend  the  enclosing  material'same  as  gunpowder. 

Explanation.  Analysis  shows  that  the  composi- 
tion of  the  altered  cotton  leads  to  the  formula 
C6H7N3011,  the  substance  having  become  a  nitro 
body.  Three  atoms  of  hydrogen  have  been  removed 
from  the  cellulose  and  in  their  places  have  been 
substituted  3N  +  60  =  3N02.  We  can  represent 
this  graphically  thus : 

_H_ 
C6H7^  -H-   5O5,  Cotton  or  cellulose ; 


272  CHEMISTRY    SIMPLIFIED. 


Trinitrocellulose. 


The  change  can  be  represented  by  the  equation  : 

305  +  3H20 


There  is  no  evolution  of  gas.  The  water  is  taken 
up  by  the  concentrated  H2S04  and  the  UNO3 
suffers  no  loss  of  energy  through  dilution.  If  ordi- 
nary cone.  HNO3  be  taken,  a  different  product  re- 
sults. It  appears  the  same  to  the  eye,  but  dissolves 
in  a  mixture  of  alcohol  and  ether.  The  product  is 
essentially  C6H8(N02)205  ==  dinitrocellulose.  It 
bears  the  name  pyroxyline  and  its  ether-alcohol  solu- 
tion is  called  collodion.  Collodion  produces  a  trans- 
parent film  when  allowed  to  run  over  a  clean  glass 
plate.  This  is  the  film  used  in  the  wet  plate  process 
of  photography.  It  is  also  used  in  surgery  to  keep 
a  fresh  wound  from  contamination  with  the  poison 
microbes  of  the  air. 

Gun-cotton  (trinitrocellulose)  as  an  explosive.  The 
products  of  the  detonation  of  gun-cotton  are  CO  + 
N  -h  CO2  +  H20.  Two  molecules  will  give  9CO  + 
3C03  +6N  +  7H20. 

1  molecule  C6H7(N02)305  weighs  72  +  7  +  138 
+  80  =  297. 

2  x  297  =  594   grams   of  C6H7(N02)305   give 
250CO  +  132C02  +  84N  +  126H20.     1  gram  of 
C6H7(N02)305    gives   0.4242CO  +  0.2222C02  + 
0.1414N  -f  0.2121H20  =  0.9999  substance. 


CARBON    COMPOUNDS.  273 

Since  1  c.c.  CO  weighs  at  0°  C.  (760  mm) 

=  0.00125  gr. 

1  c.c.  CO2  =0.001977  gr. 

1  c.c.  N  =  0.001256  gr. 

1  c.c.  H20  (steam)  at  100°  C.  =  0.000589  gr. 
Therefore  0.4242  gram   CO    occupy  the    space    of 
0.4242 


0.2222  gram  CO2  occupy  the  space  of 
0.2222 
000199~ 

0.1414  gram  N  occupy  the  space  of 
0.1414 

.  I    ]  X     ft   p 

0001257 

0.2120  gram  H20  occupy  the  space  of 

°-212Q     =  360  c.c. 
0.0005896 

But  the  volume  V,  equal  to  (339  +  112  +  113)  = 
564  c.c.  of  CO  +  CO2  +  N  at  0°  C.,  will  be  at  100° 
C.  equal  to  564  +  (564  X  0.37)  =  772  c.c.,  and  the 
total  gas  at  100°  C.  =  772  +  360  =  1132,  or  over 
three  times  the  volume  of  the  gases  which  are  evolved 
from  1  gram  of  black  powder.  Assuming  that  1 
gram  of  gun-cotton  fills  the  space  of  1  c.c.,  and  that 
the  sensible  temperature  of  the  gases  after  explosion 
be  1000°  C.,  after  proper  deductions  for  loss,  the 
pressure  exerted  by  the  gases  will  then  be  (for  the 
permanent  gases  alone)  772  -f-  285  =  1057  atmos- 
pheres per  6  sq.  centimeters.  For  the  aqueous 
vapor  we  get,  at  the  least,  a  pressure  of  360  atmos- 
18 


274  CHEMISTRY    SIMPLIFIED. 

pheres  per  6  square  centimeters,  a  total  of  1417 
atmospheres  pressing  upon  6  square  centimeters.  1 
square  inch  =  6.452  square  centimeters.  Hence  we 
get  1417  X  15  =  21255  Ibs.  pressure  on  one  square 
inch  nearly.  When  used  in  underground  workings 
the  air  becomes  poisoned,  partly  by  the  carbon 
monoxyd,  but  chiefly  from  the  brown  niter  gases, 
NO2.  This  shows  that  the  explosion  does  not  break 
up  the  gun-cotton  always  alike.  NO  forms  instead 
of  CO2,  and  then  after  explosion,  when  the  gases 
mix  with  the  air,  NO  becomes  NO2. 

THE  ACTION  OF  HEAT  UPON  CELLULOSE.      DESTRUCTIVE 
DISTILLATION  OF  WOOD.       CHARCOAL  MAKING. 

Let  a  splinter  of  dry  wood  be  heated  over  an  open 
flame,  in  a  narrow  glass  tube  which  has  been  closed 
at  one  end.  We  notice  the  wood  burning  first  yel- 
low, then  brown,  then  black,  while  a  dense  yellow 
vapor  is  evolved.  The  vapor  condenses  partly  into 
a  brown-red  liquid.  The  vapor  escaping  from  the 
tube  bums,  is  inflammable.  In  order  to  study  each 
of  these  three  main  products,  one  must  repeat  the 
experiment  on  a  larger  scale,  and  so  that  the  pro- 
ducts may  be  completely  collected,  especially  the 
gas.  The  following  arrangement  of  apparatus  Fig. 
76  will  answer  and  yet  be  simple. 

A  strong  glass  tube  T  closed  at  one  end  lies  in  a 
furnace  Fas  in  the  previous  experiment.  The  tube 
holds  a  stick  of  dry  wood  20  grs.  in  weight.  The 
tube  T  reaches  into  a  glass  receiver  R,  home-made 
from  a  large  test-tube.  A  rubber  band  2  makes  this 


CARBON    COMPOUNDS. 


275 


connection  tight.  B  is  an  open  bell  jar  with  stop- 
cock 6  connected  by  angle  tube  5  and  rubber  tube  4 
with  the  receiver.  The  bell  stands  in  a  large  beaker 
glass  H,  two-thirds  full  of  water.  With  open  stop- 
cock 6  and  sucking  at  the  rubber  tube  4  the  bell  is 
filled  with  water  ;  the  stop-cock  6  is  then  closed. 
Live  charcoal  is  piled  into  the  furnace  to  the  left  of 
the  shield  S.  The  distillation  begins ;  the  gases 
drive  the  air  out  of  2  and  R.  As  soon  as  the  yel- 
low cloud  fills  Rt  we  connect  the  rubber  tube  4  with 
R,  and  by  so  doing  will  have  fair  assurance  that 

FIG.  76. 


whatever  gases  are  now  collecting  in  B  will  have 
been  produced  from  the  breaking  up  of  the  cellulose 
molecule.  Care  is  taken  to  give  T  a  slight  inclina- 
tion forward,  to  wit,  by  raising  the  closed  end.  The 
condensed  liquid  will  then  run  into  R,  and  not  back- 
ward, where  it  might  cause  a  breaking  of  red-hot 
glass.  When  the  flow  of  gas  becomes  slower  we 
move  S  into  the  position  7,  and  fill  in  fresh  live  coal. 
Be  watchful  of  the  glass  tube  T.  If  its  temperature 
rises  above  cherry  redness  it  is  apt  to  bulge  out,  be- 
come weak  and  perforated,  an  event  which  prema- 


276  CHEMISTRY    SIMPLIFIED. 

turely  ends  the  experiment.  We  maintain  the  heat 
until  the  volume  of  gas  in  B  becomes  stationary. 
All  this  time  we  have  been  lifting  the  bell  B  so  that 
the  liquid  inside  remained  higher  than  the  outside 
level,  which  means  a  steady  suction  or  partial 
vacuum.  The  latter  is  an  additional  precaution 
against  the  distention  or  bulging  of  the  softened, 
red-hot  glass  tube.  If  now  a  mark  is  made 
upon  the  bell  to  indicate  the  height  of  the  level 
when  water  stands  evenly  inside  and  outside,  (the 
coal  being  removed  and  the  tube  having  acquired 
ordinary  temperature)  we  will  have  the  volume  of 
gas  V  which  can  be  obtained  from  the  distillation 
of  20  grams  of  dry  wood.  We  then  close  the  stop- 
cock 61,  and  set  aside  the  bell  and  holder.  We  detach 
the  receiver  and  weigh  it  with  contents,  then  with- 
out contents,  and  thus  find  the  weight  of  the  latter. 
Lastly  we  take  out  the  charcoal  from  the  tube  and 
find  its  weight. 

(1)  The  charcoal.    Varies  in  color  from  red-brown 
to  deep  black,  according  to  the  temperature.     The 
higher  the  heat,  the  deeper  the  black.     The  brown 
charcoal  is  imperfectly  done,  as  shown  by  the  fol- 
lowing analysis:    C,  70.4;  H,  4.6;  0,  24.2;  ashes, 
0.85. 

But  even  the  hardest  and  blackest  charcoal  is  not 
all  carbon;  temp.  1300°  C.  :  C,  90.8;  H,  1.6;  0, 
6.5 ;  ashes,  1.15. 

(2)  The  brown  liquid.     Even  in  the  receiver,  R, 
one  notices  that  the  liquid  consists  of  two  parts ; 
one  watery,  mobile,  brown  liquid,  we  designate  pyro- 


CARBON    COMPOUNDS.  277 

ligneous  acid ;  the  other  portion,  dark  black -brown, 
viscous,  not  very  liquid,  shall  be  named  wood-tar. 
Both  portions  possess  a  penetrating,  peculiar,  not 
unpleasant  odor — the  odor  of  smouldering  wood, 
empyreumatic  odor  from  Greek,  fire  odor.  The  taste 
of  both  portions  is  bitter,  unpleasant.  Some  of  the 
tar  collects  over  the  pyroligneous  acid,  some  at  the 
bottom,  and  some  remains  suspended.  This  proves 
tar  to  be  a  mixture  of  several  bodies.  The  pyroligne- 
ous acid  is  so  named  because  of  its  acid  reaction  on 
litmus,  and  from  pyro,  fire ;  lignum,  wood,  firewood 
acid.  Let  the  two  portions  be  separated  by  filtering 
through  charcoal  powder  which  lies  in  a  cotton- 
plugged  funnel.  The  tar  particles  adhere  to  the 
charcoal,  pyroligneous  acid  passing  through.  We 
add  solution  of  NaOH  until  the  acid  reaction  on 
litmus  ceases.  We  bring  the  liquid  into  a  flask  with 
perforated  stopper,  a  glass  tube,  bent  over  so  as  to 
connect  with  a  cooling  tube,  passing  through  the 
hole.  On  boiling,  a  colorless  liquid  passes  over 
which  shows  the  strong  odor  still  very  markedly. 
But  the  liquid  is  inflammable  ;  its  specific  gravity 
is  less  than  water.  This  substance  is  known  as 
wood  spirits.  A  closer  study  reveals  that  this  liquid 
may  be  separated  by  fractionating  into  water  plus 
concentrated  spirits,  and  the  latter  again  fraction- 
ated gives  the  pure  wood  spirits,  also  known  as 
wood  akohol,  methyl  alcohol.  It  is  a  very  mobile 
liquid,  which  boils  at  60.5°  C.  Its  specific  gravity 
at  4°  C.  =  0.81  (water  =  1).  Mixes  with  water  in 
all  proportions.  Burns  with  bright  bluish  hot 


278  CHEMISTRY    SIMPLIFIED. 

flame.     It  is  very  useful  in  the  chemistry  of  dye- 
stuffs  as  a  solvent  and  modifying  agent. 

The  analysis  gives  for  it  the  symbol  CH40.  We 
evaporate  the  remaining  liquid  in  a  boiling  flask  to 
dryness.  A  black  mass  results  which  we  calcine  in 
a  porcelain  dish,  that  is  heated  over  the  open  flame 
until  the  black  color  has  become  grey-oily;  gases  and 
vapors  pass  off.  We  return  it  then  to  the  distilling 
flask  with  H2S04  and  water.  A  colorless  liquid 
condenses,  very  mobile,  very  sour.  Because,  we 
reason,  if  the  original  acid  in  the  pyroligneous  liquid 
be  HA  then  by  adding  NaHO  we  get  NaA  +  H2O. 
Then  acting  with  H2S04  must  give  us 
2NaA  +  H2S04  ==-Na2S04  +  2HA  (the  new  acid). 

The  analysis  gives  for  HA  the  formula 
H.C2H302.  We  name  it  acetic  acid  from  acetum  = 
Latin  for  vinegar,  for  the  acid  resulting  from  the 
fermentation  of  fruit  juices  has  the  same  composi- 
tion and  properties  as  this  wood  acid.  Acetic  acid 
H.C203O2 — short  symbol,  HA — is  a  liquid,  colorless 
mobile;  with  very  sharp  odor.  At  0°  C.  this  liquid 
acid  becomes  solid,  crystallizes ;  and  strangely  these 
crystals  only  melt  at  16°  C.,  having  sp.  gr.  1.0553. 
This  most  concentrated  acid  is  known  as  glacial 
acetic  acid.  When  water  is  mixed  with  this  glacial 
acid,  the  specific  gravity  increases  although  the 
water  is  less  heavy.  This  can  only  be  explained 
by  assuming  that  the  molecules  of  the  strong  acid 
are  in  their  free  state  farther  apart  than  in  the 
water-mixed  state,  that  the  addition  of  water  causes 
the  drawing  together  of  these  molecules.  The  spe- 


CARBON    COMPOUNDS.  279 

cific  gravity  increases  until  22  parts  of  water  have 
been  added  to  78  pts.  of  acid,  when  the  specific 
gravity  =  1.0748.  Beyond,  with  more  water  the 
specific  gravity  decreases.  A  mixture  of  acid  43, 
water  57  has  again  the  same  specific  gravity  as  the 
pure  acid.  HA  forms  salts  with  all  metals  except 
gold;  and  the  normal  salts  are  all  easily  soluble  in 
water.  The  acetates  are  much  used  in  dyeing,  espec- 
ially Pb(A)2  and  A1(A)3.  In  the  manufacture  of 
charcoal,  the  pyroligneous  acid  is  neutralized 
with  Ca(HO)2  slaked  lime,  in  place  of  Na(HO) 
because  cheaper.  Hence  the  crude  Ca(A)2  is  the 
product  of  commerce,  shipped  from  the  woods  to 
the  large  cities,  where  the  acid  itself  is  then  dis- 
tilled. 

(3}  The  tar  or  wood  tar.  It  has  been  stated  above 
that  by  this  name  is  meant  the  oily  dark-colored 
material  which  either  rises  as  a  scum  to  the  top  of 
the  wood  acid,  or  sinks  to  the  bottom  of  the  latter. 
We  separate  it  from  the  watery  liquid  and  proceed 
to  its  examination.  The  expression  Tar-jacket  for 
a  sailor  came  in  use  through  someone's  observing 
that  the  steeping  of  wood  or  linen  in  tar,  made 
those  substances  impervious  to  water,  and  prevented 
both  dry-rot  and  wet-rot  (the  decaying  of  wood). 
Hence  the  practice  rose  to  soak  the  wooden  planks 
of  boats  and  ships  with  the  tar,  also  the  entire 
rigging,  especially  halyards  and  shrouds  and  cables, 
also  the  overalls  of  the  sailors,  with  this  strong- 
smelling  material.  Later  on  fence  posts,  telegraph 
poles,  etc.,  were  steeped,  and  lastly,  railroad  ties. 


280 


CHEMISTRY    SIMPLIFIED. 


Evidently  mine  timber  would  be  benefited  by 
means  of  repeated  coats  of  tar,  wherever  mines  are 
half  wet,  and  the  timbers  succumb  rapidly  to  the 
rot,  i.  e.,  fungus  and  microbes.  The  curing  of  hams, 
bacon,  fish,  by  first  salting  and  then  drying  them 
out  over  a  smoking,  smouldering  wood  fire,  is  a  very 
ancient  practice.  The  tar  oils  condense  on  the  sur- 
face of  the  meat  and  keep  off  the  microbes  of  putre- 
faction until  the  meat  is  dried  out  and  no  longer 

FIG.  77. 


subject  to  the  action  of  these  organisms.  Tar  burns 
freely  and  is  used  as  a  so-called  liquid  fuel.  Let 
the  tar  be  heated  in  a  retort,  which  is  furnished 
with  a  thermometer,  Fig.  77,  i;  the  neck  of  the  re- 
tort reaching  by  a  reducer  B,  the  tube  of  a  Liebig 
cooler  L,  the  joint  R-N  made  tight  by  a  rubber 
band.  Cold  water  enters  from  a  hydrant  through 


CARBON    COMPOUNDS.  281 

connecting  rubber  1  into  the  cooler,  the  warm  water 
leaving  through  rubber  tube  2.  The  flame  from 
burner  F  is  so  regulated  that  the  liquid  keeps  gently 
boiling.  We  notice  that  the  mercury  in  thermometer 
will  be  steadily  rising,  while  a  clear  liquid  collects 
in  the  graduate  G.  The  rising  thermometer  can 
mean  two  things :  (a)  The  tar  is  a  mixture  of 
liquids  having  their  boiling  points  at  different  tem- 
peratures, (b)  The  tar  is  a  uniform  chemical  sub- 
stance, which,  however,  breaks  up  by  the  heat  into 
bodies  of  different  boiling  points.  Evidently  it 
makes  no  difference  for  practical  purposes  whether 
the  truth  lies  in  condition  (a)  or  whether  it  lies  in 
condition  (b).  If  the  graduate  G  be  emptied  when 
10  c.c.  have  been  condensed,  and  so  every  other  10 
c.c.  be  collected  separately  (distillation  by  fractions), 
it  will  be  found  that  the  specific  gravity  of  each 
fraction  is  higher  than  that  of  the  preceding  fraction, 
varying  from  0.82  to  0.87.  Before  the  Pennsylvania 
coal  oil  had  come  into  general  use,  these  tar  oils 
took  the  place  as  illuminating  agents,  the  lighter 
part  going  by  the  name  of  photogen,  while  the  heavier 
part  was  known  as  solar  oil.  To  the  latter  clung  the 
strong  penetrating  odor.  If  this  portion  be  shaken 
with  NaOH  or  KOH  in  water-solution  for  some 
time,  and  the  two  liquids  be  allowed  to  stand 
quietly,  they  will  separate,  the  oil  above,  the  KOH 
water-solution  below.  In  a  separately  funnel  the 
aqueous  liquid  can  be  drawn  off  clean.  We  make 
acid  with  dilute  H2S04,  and  find  again  an  oil 
separating  at  the  top.  This  oil  possesses  a  penetrat- 


282  CHEMISTRY    SIMPLIFIED. 

ing  odor,  and  a  bitter  astringent  taste.  It  used  to  be 
called  creosote,  is  now  called  carbolic  acid  or  phenyl 
hydroxyd.  The  combustion  analysis  (refer  to  cellu- 
lose) gives  the  ratio  of  the  elements  as  C5H60,  but 
because  this  body  as  we  have  seen  combines  with 
KOH,  and  because  it  also  dissolves  in  strong  H2S04, 
we  write  its  formula,  C6H5(HO).  C6H5  as  radical 
we  call  phenol  or  phenyl.  Towards  strong  bases  it 
acts  as  an  acid,  towards  strong  acids  as  a  base. 
Thus : 

KOH  +  C6H5(HO)  =  H20  +  (KO)C6H5,  .potas- 
sium carbolate. 

2C6H5(HO)  +  H2S04  =  C6H5.H(S04) .+  H20  - 
phenyl  sulfate  -1-  water. 

Carbolic  acid  or  creosote  is  at  ordinary  temperature 
a  crystallized  solid  without  color,  but  possessing  a 
strong  smell.  It  melts  quickly  into  a  thick  oil. 
One  part  dissolves  in  10  parts  of  water.  It  is  very 
poisonous  to  animal  life.  It  is  used  as  a  germ- 
destroyer,  but  its  chief  use  is  to  act  as  base  for 
the  manufacture  of  picric  acid.  Coal-tar  contains 
more  carbolic  acid  than  wood-tar. 

Trinitrop  heno  I,  CfiH2  ( NO 2 ) 3  OH,  picric  acid.  Take 
about  1  c.c.  of  liquid  carbolic  acid.  Pour  this  into 
10  c.c.  of  fuming  HNO3.  The  action  is  apt  to  be 
violent,  copious  brown  fumes  being  formed.  Boil 
until  brown  fumes  stop.  Then  pour  liquid 
into  much  cold  water.  The  water  takes  a  deep 
yellow  color  and  a  yellow  sediment  falls  oufr.  The 
yellow  substance  is  picric  acid.  Pour  off  the  yellow 


CARBON    COMPOUNDS.  283 

liquid  and  add  to  the  residue  again  about  50  c.c.  of 
water,  and  boil.  The  picric  acid  being  more  soluble 
in  boiling  water,  a  brown  resin-like  substance  re- 
mains. As  the  boiling  yellow  liquid  cools  down  it 
throws  out  yellow,  scaly  crystals,  the  picric  acid; 
picros  =  bitter,  on  account  of  the  strong  bitter  taste. 
Solution  reddens  litmus  ;  can  be  neutralized  with 
KOH  or  NH4HO  when  yellow  needles  fall  from  the 
solution,  representing  the  potassium,  or  ammonium 
picrate.  Both  these  salts  are  very  explosive,  more 
so  than  the  acid  itself.  The  ammonium  picrate  is 
used  in  the  smokeless  powders. 


C6H2(N02)3HO  +  NH4HO  =  (NH4)O.C6H2- 
(NO2)3  +  H20. 

The  solution  of  picric  acid  is  used  in  dyeing  silk  and 
wool  a  beautiful  golden-yellow  color. 

Paraffin,  C11H36  to  C24#50.  On  continuing 
the  distillation  of  the  tar,  after  the  solar  oil  sp.  gr. 
0.86,  we  find  that  the  vapors  condense  in  the  tube  to 
LI  semi-liquid,  buttery  product,  and  finally  they  con- 
dense to  a  rigid  solid.  By  pressing  the  semi-liquid 
between  paper,  we  find  scaly  crystals  in  the  paper 
and  a  liquid  pressed  through  the  latter.  The  liquid 
is  known  as  paraffin  oil  for  lubrication,  and  the  crys- 
tals go  under  the  name  of  paraffin.  So  also  does  the 
material  which  solidifies  at  once  into  a  rigid  solid. 
After  refining,  the  paraffin  is  used  for  imitation  ivax 
candles.  As  given  above,  the  solid  is  not  a  homo- 
geneous body,  but  a  succession  of  hydrocarbons  of 
the  general  formula  CnH2n+2.  The  melting-point  is 


284 


CHEMISTRY    SIMPLIFIED. 


the  arithmetical  mean  of  those  of  the  different  mem- 
bers. 

Paraffin  is  useful  in  the  laboratory  to  soak  corks 
in,  to  paint  over  labels  with,  and  in  fact  to  cover  all 
metallic  apparatus  which  is  not  subjected  to  heat, 
for  it  is  a  body  very  indifferent  to  chemical  action. 

Only  hot  concentrated  HNO3  or  hot  H2S04  will 
decompose  it. 

Examination  of  the  ivood  gases.  In  this  examina- 
tion we  make  use  of  the  solubilities  of  the  gases  in 

FIG.  78. 


liquids  or  their  absorption  by  solids.  The  sum  of 
the  processes  we  designate  as  gas  analysis.  The  most 
convenient  apparatus  for  the  purpose  has  been  de- 
signed by  Professors  Winkler  and  Hempel ;  though 
a  number  of  others  of  no  less  ingenuity  have  con- 


CARBON    COMPOUNDS.  285 

tributed  their  share.  In  Fig.  78  B  represents  the 
burette  or  measuring  vessel,  a  cylindrical  glass  tube 
graduated  into  100  c.c.  and  4-  c.c.  The  tube  stands 
in  the  cast-iron  foot  F  so  that  it  will  not  be  upset 
easily.  .Fis  bored  out  at  1  to  admit  a  small  tubu- 
lature  to  which  a  strong  rubber  tube  is  wired.  The 
stop-cock  S  has  a  capillary  perforation  which  leads 
to  the  capillary  tube  3.  With  the  latter  is  united 
by  the  wired  rubber  5  the  capillary  transfer  tube  4  in 
form  of  a  double  L.  The  hollow  volumes  or  canals 
of  both  tubes  do  not  exceed  0.01  c.c.  L,  Fig.  78,  is 
the  level  tube  in  foot  .Pto  which  the  rubber  tube  from 
foot  of  B  is  joined  and  wired  at  6,  The  rubber  tube 
should  be  as  long  as  the  cylinder  is  high,  so  that  the 
foot  of  one  cylinder  may  be  raised  to  the  top  of  the 
other  cylinder.  This  arrangement  permits  the  read- 
ing of  the  gas  volume  under  constant  pressure,  i.  e., 
the  pressure  of  the  atmosphere,  and  in  so  much  as 
the  temperature  of  the  room  does  not  materially 
change  during  one  set  of  absorptions,  we  may  set 
down  the  temperature  as  constant  and  thus  avoid  the 
reductions  of  volumes  to  0°  C.  and  760  mm. 

Fig.  79  shows  the  pipette  or  absorption  vessel  for 
absorbing  CO2.  The  glass  bulb,  C,  is  seen  filled 
with  small  coils  of  iron  wire  gauze,  which  are  in- 
troduced by  means  of  the  wide  mouth  and  stopper 
at  S.  This  bulb  communicates  through  tube,  1, 
with  the  reservoir-bulb,  D,  which  is  open  at  the  top. 
A  capillary  glass  tube  leads  in  single  loop  to  the 
rubber  tube,  3,  the  latter  being  closed  by  the  pinch- 
cock,  4..  The  whole  combination  is  fastened  to  the 


286 


CHEMISTRY    SIMPLIFIED. 


iron  frame,  F,  which  has  taken  the  place  of  the 
former  wooden  frame,  the  spilling  of  the  strong 
agents  over  the  wood  making  it  soon  unsightly  and 
insecure  to  stand  up.  The  absorbing  liquid  is  a 
solution  of  15  grams  of  KOH  or  NaOH  in  50  c.c.  of 
water.  This  solution  is  poured  into  D  (pinch-cock 
being  open) ;  the  air  is  forced  into  D,  the  pressure 
driving  the  liquid  gradually  through  the  capillary 

FIG.  79. 


tube  leading  to  3,  until  the  liquid  appears  at  the 
top  of  3.  The  coils  of  iron  wire  gauze  being  moist- 
ened with  the  alkali,  expose  a  very  large  surface  to 
the  gas  and  cause  an  almost  instantaneous  absorp- 
tion of  the  CO2. 

Fig.  80  represents  a  double  pipette,  to  be  used 
for  liquids  which  are  easily  deteriorated  by  the 
oxygen  of  the  air,  like  potassium  pyrogallate  for 
oxygen,  and  acid  or  ammoniacal  solution  of  Cu2Cl2 
for  CO.  The  capillary  is  provided  with  a  pinch- 
cock,  as  in  previous  form.  Being  filled  as  the 


CARBON    COMPOUNDS. 


287 


figure  indicates,  the  bulb,  A,  being  the  absorp- 
tion bulb,  is  quite  full,  whilst  the  liquid  rises  in  B 
only  to  the  lower  outlet.  C  contains  the  same 
liquid,  but  only  partially  filled.  Hence  the  air  has 
no  access  to  the  liquid  in  A  and  B,  and  can  spoil 
only  the  liquid  in  C  and  D.  When  the  gas  enters 
A  through  the  capillary,  it  pushes  the  absorption 

FIG.  80. 


fluid  into  B,  which  is  large  enough  to  hold  the  entire 
volume  of  A.  As  the  fluid  rises  in  B,  the  nitrogen 
forces  down  the  liquid  in  C  until  the  bubbles  can 
pass  into  D,  and  when,  after  the  absorption,  the  gas 
leaves  A  returning  to  the  burette,  air  will  bubble  from 
D  into  C.  But  it  loses  its  oxygen  to  the  liquid,  and 
thus  there  is  only  nitrogen  between  the  levels  in  B 
and  C.  In  others  words,  C  and  D  are  simply  traps. 
The  pipette,  Fig.  81,  serves  when  the  absorption 
liquid  attacks  metal  and  yet  a  large  wet  surface  is  to 
be  exposed  to  the  gas ;  using,  for  instance,  oil  of  vitriol 


288 


CHEMISTRY    SIMPLIFIED. 


or  bromine  water.  Here  the  bulb  B  is  filled  with  glass 
beads.  These  were  put  in  by  the  glass  blower  before 
he  narrowed  the  neck  which  unites  B  to  A.  Through 
the  glass  blower's  dexterity  we  are  thus  in  posses- 
sion of  an  elegant  set  of  apparatus.  But  suppose 
one  of  the  pipettes  meets  with  disaster  just  when 

FIG.  81. 


you  need  the  set  most.  What  then?  A  week 
would  pass  before  you  get  a  duplicate  from  the 
dealer.  Fig.  82  shows  how  an  equivalent  may  be 
made  quickly  by  means  of  2  Erlenmeyer  flasks,  E, 
E'.  The  flasks  should  hold  200  c.c.  each.  The 
flasks  have  doubly-perforated  stoppers.  Through 
one  of  the  holes  passes  the  siphon  tube  1,  \"  inside 
diameter,  reaching  to  near  the  bottom  of  both  flasks. 
Into  the  second  hole  of  stopper  E  is  stuck  a  piece  of 
thermometer  tube — there  are  always  broken  ther- 
mometers about  a  laboratory.  The  thermometer 
has  a  capillary  canal,  just  what  we  need.  The  piece 


CARBON    COMPOUNDS. 


289 


is  about  2J  inches  long;  the  sharp  edges  are  rounded 
over  a  flame;  the  tube  is  stuck  in  so  that  the  lower 
edge  is  flush  with  the  stopper,  avoiding  any  spaces 
for  the  lodging  of  gas.  A  piece  of  rubber  tubing 
(black)  2"  long  is  wired  over  the  upper  end  and  a 
pinch-cock  clamped  just  above  the  end  of  the  cap- 
illary tube.  Through  the  second  hole  of  stopper 
E'  passes  a  short  glass  tube  #,  £"  inside,  to  which  a 
piece  of  rubber  tubing  4-  is  attached  (for  conveni- 
ence in  blowing  air).  E  may  be  filled  with  coils  of 
iron  wire  gauze,  or  with  glass  beads  to  give  absorb- 

FIG.  82. 


ing  surface.  In  filling  with  absorption-liquid  re- 
move stoppers,  pour  into  each  flask  so  that  the 
levels  are  even  and  nearly  up  to  J  vol.  of  flask. 
Then  insert  stoppers  very  tightly,  open  pinch-cock 
and  blow  into  rubber  tube  4-  until  the  liquid  ap: 
pears  above  the  pinch-cock;  then  close  the  latter 
and  E  will  remain  full,  ready  to  receive  the  gas. 
The  two  flasks  form  one  unit.  To  prevent  deteri- 
oration of  stoppers,  they  should  be  coated  with 
19 


290 


CHEMISTRY    SIMPLIFIED. 


molten  paraffin  and  after  pressing  them  into  the 
necks,  copper  wire  should  be  stretched  across  the 
tops  to  prevent  their  slipping  out,  as  the  paraffin  is 
a  splendid  lubricator.  Such  an  apparatus  gives 
perfect  results.  If  the  measuring  cylinder,  the 
burette,  should  break,  you  can  construct  a  very 
satisfactory  substitute  as  follows :  Make  a  square 
block  of  wood  4"  side  length  and  3"  thick.  Bore 
an  inch  hole  clear  through  the  center  and  a  slot  S, 
Fig.  84,  clear  through  the  side,  J"  wide.  Then  nail 

FIGS.  83,  84,  85. 


a  square  of  heavy  sheet  lead  (J"  thick)  across  the 
bottom  as  at  L,  Fig.  83.  The  top  edges  of  the  block 
should  be  bevelled.  This  will  give  you  an  excellent 
stand,  or  foot  for  the  burette.  Select  a  piece  of 
glass  tube  as  nearly  cylindrical  as  possible  of  from 
•f  "  to  J"  inside  dia.  about  three  feet  long.  Scrub 
the  inside  of  the  tube  with  warm  NaOH  solution  to 


CARBON    COMPOUNDS.    ,  291 

remove  any  fat;  then  rinse  and  dry.  Round  off 
the  sharp  edges  of  one  end,  fit  a  cork  or  rubber 
stopper  with  one  hole,  into  which  you  have  put  a 
J"  glass  tube,  bent  as  shown  at  t,  Fig.  83.  Close  t 
with  a  bit  of  wax  plug ;  then  set  it  into  the  foot, 
after  first  sticking  some  cotton  into  the  hole.  Fill 
with  water  to  about  1  inch  above  the  wood  and 
scratch  with  a  file  a  line  ra  at  the  upper  rim  of  the 
meniscus.  Weigh  into  a  beaker  glass  100  grams  of 
water  not  nearer  than  10  mgr.  which  is  equal  to 
0.01  c.c.  Pour  this  water  into  the  tube.  But  re- 
member that  the  beaker  as  well  as  the  tube  should 
be  moistened  before  either  weighing  or  pouring,  for 
some  water  will  adhere  to  the  glass  wall,  thus  caus- 
ing an  error. 

Now  make  another  scratch  at  the  upper  rim  of 
the  meniscus  ra'.  Now  empty  the  tube  and  cut  off 
the  latter  1"  above  ra'  at  ra",  round  off  the  sharp 
edges  over  the  flame  and  fit  a  stopper  into  which 
you  have  stuck  2"  of  thermometer  tube,  the  edge  of 
the  latter  being  flush  with  the  under  side  of  the 
stopper.  Fasten  a  strip  of  white  writing  paper 
(several  lengths  may  be  stuck  together)  and  lay  off 
upon  it  the  distance  ra-ra/  accurately.  Divide  this 
space  into  100  equal  parts,  and  -each  part  into  fifths. 
Number  every  10  c.c.  and  draw  out  in  india 
ink,  cut  it  into  a  strip  \"  wide,  paste  upon  the  tube 
with  a  mixture  of  starch  paste  and  liquid  glue. 
Remember  that  the  wet  paper  expands  and  that  the 
two  end  marks  will  fall  beyond  the  scratches  on  the 
glass.  In  drying  the  contraction  will  bring  the 


292  CHEMISTRY    SIMPLIFIED. 

paper  back  to  the  mark.  When  dry  cover  the  back 
of  the  paper  with  molten  paraffin,  but  not  the  glass. 
Press  down  the  upper  stopper  so  that  its  under  face 
coincides  with  the  zero  mark  m'  as  shown  in  figure  ; 
the  remainder  of  tube  being  already  cut  off.  Now 
fasten  the  tube  into  the  foot  by  pouring  liquid  wax 
into  the  narrow  ring  between  glass  and  wood,  the 
slot  having  been  plugged  with  wood.  Finally  put 
2"  of  rubber  tube  upon  the  capillary  and  a  pinch- 
cock.  Thus  the  top  of  the  burette  will  look  as  shown 
in  Fig.  85.  It  is  in  every  respect  as  good  as  a  fully 
glass  blown  instrument,  except  that  the  scale  is  not 
apt  to  be  quite  as  accurate,  yet  sufficient  for  all 
technical  purposes.  Never  omit  the  wiring  of  the 
rubber,  for  if  the  rubber  slips  off  the  examination  is 
lost.  The  analysis  of  our  wood  gas  can  now  be  pro- 
ceeded with. 

Note.  All  gases  are  more  or  less  soluble  in  water. 
To  avoid  the  error  from  this  source  completely  the 
gas  must  be  caught  over  mercury  and  measured 
over  mercury — level  glass  and  burette  are  filled  with 
mercury.  The  error  may  be  overcome  partially,  by 
saturating  the  water  in  the  burette  with  the  gas,  i. 
e.j  shaking  the  water  with  the  gas,  and  the  same 
with  the  absorbing  liquids.  The  most  soluble  in 
water  is  CO2,  hence  it  is  well  to  let  water  in  burette 
saturate  itself  with  CO2,  before  the  analysis. 

To  fill  the  burette  with  gas  from  the  holder  will 
be  the  first  operation,  taking  advantageously  just 
100  c.c.  to  avoid  figuring.  In  Fig  86  the  arrange- 
ment of  apparatus  is  shown  in  the  moment  of  trans- 


CARBON    COMPOUNDS. 


293 


fer,  when  the  gas  has  passed  from  B  into  the  ab- 
sorption bulb  A,  and  the  liquid  from  the  latter  into 


FIG.  86. 


the  tank  bulb  C.     Stop-cock  1  and  pinch-cock  2  are 
now  closed ;  the  level  cylinder  dropped  upon  the 


294  CHEMISTRY    SIMPLIFIED. 

table.  The  operator  seizes  the  frame  of  the  pipette 
and  the  scaffold  upon  which  the  pipette  stands,  with 
both  hands  and  shakes  so  that  the  liquid  in  A 
splashes  all  about  the  bulb  and  remains  in  contact 
with  the  gas  ;  at  the  least  for  5  minutes.  Then  open 
the  cocks  and  the  gas  will  flow  back  into  B  where 
the  vol.  is  recorded. 

The  order  in  which  the  absorbents  are  applied  is : 
(1)  KOH for  CO2  :  (2)  pyrogallate  for  O  ;  (3)  fuming 
sulfuric  hydrate  (oil  of  vitriol)  for  the  heavy  hydro- 
carbons;  (4)  cuprous  chlorid  in  ammoniacal  or  in 
HC1  solution  for  CO  ;  (5)  spongy  metallic  palladium 
forH. 

In  applying  these  to  our  gas,  the  gas  from  cellu- 
lose or  wood,  we  find  a  shrinkage  of  volume  after 
each  application,  except  for  oxygen.  This  element 
is  only  found  when  air  has  become  mixed  with  the 
gas.  The  largest  shrinkage  is  that  due  to  hydrogen. 
After  the  absorption  of  H  by  palladium  there  is 
still  a  large  volume  of  gas  left.  It  must  be,  there- 
fore, a  gas  which  we  have  not  met  with  before.  We 
find  it  to  be  highly  inflammable,  and  it  burns  with 
a  pale,  nearly  colorless  flame,  if  ignited  at  a  platinum 
tip  (for  if  the  flame  comes  in  contact  with  glass,  the 
former  is  always  of  orange-yellow  color  from  the 
sodium  in  the  composition  of  the  glass). 

MARSH  GAS,  METHANE,  METHYLHYDRID,  CH4. 

When  the  gas  in  question  burns  we  can  easily 
demonstrate  the  forming  of  CO2  and  water,  hence  the 
gas  must  contain  C  and  H,  but  might  also  contain  0. 


CARBON    COMPOUNDS. 


295 


To  get  at  the  relative  proportions  of  C  -f  H  we 
burn  a  measured  volume  within  a  closed  vessel,  so 
that  none  of  the  products  can  escape.  Heretofore 
we  used  a  simple  eudiometer,  the  gas  being  above 
mercury.  Hempel  has  constructed  a  pipette  for 
this  purpose.  Fig.  87  shows  this  piece  of  apparatus. 
The  bulb  A  is  shaped  into  a  neck*  or  dome  and 
thence  is  fused  to  the  capillary.  Into  the  neck  two 

FIG.  87. 


platinum  wires  are  inserted  by  fusion,  the  same  as 
in  the  eudiometer ;  these  wires  lead  to  the  pole 
binders  of  an  induction  coil,  thence  to  the  battery. 
A  being  completely  rilled  with  water,  we  transfer 
from  the  burette,  say  10  c.c.  of  gas,  into  A.  We 
cannot  use  pure  oxygen,  because  the  explosion  might 
easily  shatter  the  relatively  thin  and  weak  bulb. 
We  take  air  instead,  thus  diluting  the  effect  of  the 


296  CHEMISTRY    SIMPLIFIED. 

explosion  by  means  of  the  inert  nitrogen.  100 
volumes  of  air  contain  20.9  volumes  0.  As  regards 
the  volume  of  air  to  be  admitted  we  can  reason 
thus  :  If  the  total  10  c.c.  were  carbon  gas  then  we 
would  need  20  c.c.  of  0,  for  1  vol.  of  CO2  contains 
\  vol.  C  +  1  vol.  0.  If  the  whole  10  c.c.  were 
hydrogen,  then  we  should  need  5  c.c.  of  oxygen,  a 


total  of  25  c.c.  of  oxygen  or      _  =  119  c.c.  of 

L\ 

air.  As  both  C  and  H  are  present,  this  volume  of 
air  will  surely  give  us  an  excess  of  oxygen.  Let 
this  volume  of  air  be  transferred  from  the  burette  in 
2  installments,  then  let  the  cock  S  be  closed.  The 
expansion  of  the  gases,  consequent  to  the  explosion, 
will  then  throw  itself  upon  the  bit  of  rubber  tube, 
between  the  pinch-cock  and  the  capillary,  hence 
the  rubber  tube  must  be  very  strongly  wired  upon 
the  glass,  or  the  rubber  will  be  surely  flung  off  as  a 
bullet  from  a  gun  barrel  ;  the  pinch-cock  also  must 
be  wired  so  that  it  cannot  open  under  the  pressure. 
A  screw  clamp  is,  therefore,  preferable  to  the  spring 
clamp.  The  rubber  tube  should  be  frequently  re- 
newed, as  frequent  expansion  is  apt  to  destroy  the 
elasticity  of  the  rubber.  Let  the  pipette  be  forcibly 
shaken  to  effect  a  mixing  of  air  and  gas.  Make 
connection  at  commutator  ;  the  spark  is  seen  passing 
between  the  platinum  wires,  but  no  explosion  occurs  ; 
it  should  take  place  and  mostly  does  take  place. 
When  it  does  not  occur  the  cause  of  failure  lies  in 
too  much  dilution,  the  10  c.c.  of  gas  taken  having 
already  much  nitrogen  admixed.  Under  these  cir- 


CARBON   COMPOUNDS.  297 

cu  instances  we  generate  in  a  voltameter  fulminating 
gas  (0  +  2H),  and  let,  say,  10  c.c.  into  A.  Explosion 
is  now  certain  ;  the  fulminating  gas  will  act  the 
same  as  the  cap  attached  to  the  fuse,  when  a  charge 
of  dynamite  is  to  be  exploded.  In  our  meaning 
the  term  explosion  =  instantaneous  oxydation  or 
combustion,  or  burning  of  C  and  H.  A  slower 
burning  may  be  called  a  fire.  The  volume  of  ful- 
minating gas  need  not  to  be  measured  accurately — 
because  it  simply  disappears  in  the  explosion  as 
water,  whose  volume  is  trifling  in  comparison  to 
the  volume  of  the  gas.  After  the  explosion  we 
open  cock  S  and  note  a  strong  current  setting  from 
B  into  A,  and  this  means  disappearance  of  a  certain 
portion  of  the  gas.  The  disappeared  portion  we 
name  the  contraction,  =  C',  in  this  case  30.1  c.c. 
The  volume  of  the  gas  mixture  V,  before  the  ex- 
plosion was 

V  =  G  +  A  (G  =  gas  10  c.c.  ;  A  —  air  119  c.c.) 

V==10H-119  =  129c.c. 
After  the  explosion 

V  =  V  —  C'' (contraction)  =  129  —  30.1  =  98.9 
C'  itself  is  made  up  of  H  -f  0  which  disappeared  as 
IPO. 

2C//3  =  H;  C'/3  =  0. 

We  pass  the  mixture  into  the  KHO  pipette  and  find 
a  shrinkage  of  9.8  c.c.,  which  must  represent  the  CO2 
formed  from  10  c.c.  of  the  gas.  But  1  volume  CO2 
contains  1  volume  0,  hence  9.8  c.c.  of  the  24.9  c.c. 
of  0  added  went  into  the  forming  of  CO2 ;  which 


298  CHEMISTRY    SIMPLIFIED. 

means  that  10  c.c.  of  the  gas  contained  5  c.c.  or  ^ 
vol.  carbon  vapor.  We  transfer  the  gas  into  the  pyro- 
gallate  pipette  and  shake  10  minutes  to  absorb  the 
remaining  oxygen. 

We  find  shrinkage  =  5.1  c.c.  oxygen ;  hence,  de- 
duct from  total  oxygen  =  24.9  c.c. 

Consumed  for  CO2  =    9.8  c.c. 

Remaining  oxygen  =    5.1  c.c. 


14.9 

Therefore  in  contraction  C'  enter  24.9  —  14.9  =  10 
c.c.  of  0.  And  as  hydrogen  =  f  C' ;  ozygen  JC' ;  the 
10  c.c.  of  0  correspond  to  20  c.c.  of  hydrogen,  or  if  the 
original  10  c.c.  of  gas  be  made  ==  1  vol.  it  follows 
that  1  vol.  of  our  unknown  gas  contains  J  vol.  C 
+  2  vols.  H  ;  or  1  vol.  C  +  4  vols.  H  and  its  formula 
or  symbolic  expression  is 

CH4. 

Here  we  have  a  body  representing  a  compression  of 
2.5  : 1 ;  5  volumes  of  C  +  H  compressed  into  2  vols. 
CH4.  We  have  not  had,  therefore,  a  similar  com- 
pound. Nevertheless  the  fact  is  proved  by  the 
specific  gravity  which  is  by  calculation 

J  volume  of  carbon  vapor  =  0.4146 
2  volumes  of  hydrogen       =  0.1382 

0.5528 

Several  experimenters  have  found  by  independent 
methods,  that  is,  both  by  weighing  the  gas,  and  by 
its  velocity  of  diffusion,  the  number  0.5589  which 
is  very  close  to  the  calculated  figure.  The  name 


CARBON    COMPOUNDS.  299 

marsh  gas  (sumpf  gas  in  German)  refers  to  the  evolu- 
tion of  this  same  gas  from  swampy  meadows  where 
it  sometimes  gives  rise  to  the  peculiar  phenomenon 
of  the  ivill-of-the-wisp  (irr-iicht  =  erring  or  wander- 
ing light),  when  by  accident  the  gas  becomes  in- 
flamed at  one  spot  and  the  pale  flame,  then  setting 
fire  to  the  adjacent  bubbles  thus  produces  the 
impression  of  a  wandering  or  jumping  flame,  once 
thought  to  be  spirits.  In  the  summer  months  the 
gas  always  comes  abundantly  when  the  mud  in 
swamp  rivers  is  disturbed  or  poked  into. 

Marsh  gas  has  neither  odor  nor  taste.  Mixed  with 
air  it  causes  no  ill  effects  when  breathed,  is  there- 
fore not  a  poisonous  gas  such  as  CO,  or  a  suffocating 
gas  such  as  CO2.  100  volumes  of  water  absorb  at 
20°  C.,  i.  e.,  the  ordinary  temperature  of  the  air,  3.5 
volumes  of  marsh  gas. 

When  mixed  with  8  to  10  volumes  of  air,  or  2 
volumes  of  oxygen,  the  gas  explodes  with  great 
violence  ;  but  the  temperature  at  which  it  ignites  is 
higher  than  that  at  which  hydrogen  or  hydrogen 
sulfid  explode.  These  gases  require  only  low  red 
heat,  while  marsh  gas  requires  yellow  or  white 
heat,  showing  that  the  elements  C  +  H  cling  very 
strongly  together. 

1  volume  CH4  +  3  or  4  vols.  air  does  not  explode ; 
with  1  vol.  CH 4  -(-5  J  to  6  vols.  air  the  explosion  is  weak. 
And  so  again  with  14  volumes  of  air,  the  explosion 
is  weak  ;  with  still  more  air  the  CH4  merely  burns 
over  the  flame  of  a  candle  or  lamp — no  explosion. 
Now  all  this  is  knowledge  of  extreme  importance  to 


300 


CHEMISTRY    SIMPLIFIED. 


the  engineer  who  engages  in  coal-mining.  For  CH4  is 
the  gas  which  issues  from  the  fissures  of  the  coal  beds ; 
and  causes  the  fire  danger  in  those  mines,  from  its 
life-destroying  explosions.  The  simplest  instru- 
ment for  the  detection  of  the  danger,  i.  e.,  the 
presence  of  the  marsh  gas  in  the  mine,  breasts,  stopes, 
levels,  was  devised  by  Sir  Humphrey  Davy,  eighty- 
eight  years  ago.  He  it  was  who  first  inquired  into 


Fra. 


the  nature  of  a  flame  and  thus  discovered  a  means 
against  the  ignition  of  the  inflammable  mixture  of 
air  and  marsh  gas.  Let  A,  Fig.  88,  be  the  basin  of 
an  ordinary  oil  lamp  with  a  wick  holder  and  wick 
4;  the  oil  level  at  3,  the  flame  1.  B  is  fine  mesh 
wire  cloth  made  into  a  truncated  cone  and  the  cone 
is  held  by  the  brass  ring  8.  Thus  no  air  can  get  to 


CAKBON    COMPOUNDS.  301 

the  flame  unless  it  pass  through  the  gauze,  and  the 
product  of  the  combustion  must  also  pass  through 
the  gauze,  since  the  top  of  the  cone  is  closed  by 
gauze.  If  the  air  contains  CH4  admixed,  the  flame 
begins  to  tremble,  becomes  longer  and  a  bluish 
mantle  forms  around  it.  The  whole  interior  may 
be  filled  with  such  a  blue  flame.  This  is  due  to 
the  fact  that  with  the  deficiency  of  air  the  carbon 
only  burns  to  CO  and  not  to  CO2.  But  why  does 
not  the  flame  ignite  the  outside  gas  mixture? 
Simply  because  the  wire  gauze  absorbs  the  heat  so 
quickly  that  the  temperature  outside  of  it  is  too  low 
to  ignite  the  gas.  The  wick  requires  trimming  from 
time  to  time  and  snuffing.  These  operations  are 
performed  with  the  wire  2,  which  passes  through 
a  stuffing  box  in  the  bottom  of  the  lamp.  The 
gauze  must  never  be  removed  inside  of  the  work- 
ings. Unfortunately  the  light  given  by  such  an 
affair  is  very  weak  and  thus  the  men  are  tempted 
to  remove  the  gauze  and  then  comes  the  disaster. 

Theoretical  importance  of  marsh  gas.     CH4  may 
be  written 

H 


H— C— H 


Four  hydrogen  chemical  units  evenly  balancing 
the  4  affinity  bonds  of  the  carbon  unit ;  in  other 
words  we  say  the  marsh  gas  being  a  fully  satisfied 
chemical  complex,  all  other  combinations  of  carbon 


302  CHEMISTRY    SIMPLIFIED. 

and  hydrogen  when  saturated  must  be  of  the  same 
type.      Numerically  we   can  express   it  CuH2n+2. 
When  we  found  that  paraffin  showed  the  composi- 
tion C24H50,  we  mean  that  we  have  here  a  com- 
pound built  upon  the  type  of  marsh  gas,  yet  while 
CH4  equals  a  percentage  composition  of  75C  -f  25H, 
the  percentage  in  paraffin  will  be  85.3  C  -f-  14.7  H. 
All  the  members  of  the  marsh  gas  or  paraffin  series 
have  been  found  either  as  existing  in  natural  bodies 
or  they  have  been  prepared  by  artificial  splitting. 
CH4        =  methane — marsh  gas — a  permanent. gas. 
C2H6      =  ethane,  a  condensible  gas. 
C3H8       =  propane,  a  light  liquid. 
C4H10     =  butane  (in  butter). 
C5H12     —pentane  (five). 


C6!!1'     =  hexane  (six). 
C7H16     =  heptane  (seven 


Liquids  contained  in 
gasoline,  benzine, 


C8H1!     =  octane  (eight).  and        kersosene, 

C9H20     =  nonane  (nine).  also  in  tar. 

CioH22  =  decane(ten).         J 

I    I    I 
C24H5«   =  paraffin;  a  white,  hard  solid. 

With  the  increase  of  C  in  the  molecule,  rise  the 
specific  gravity  and  the  boiling-point.  There  are 
reasons  for  assuming  in  marsh  gas  the  existence  of 
a  group  (CH3),  in  which  there  is  still  closer  contact 
between  the  atoms  than  in  CH4.  This  latter  be- 
comes then  the  hydrogen  compound  of  the  form 
(CH3)H.  The  group  (CH3)  ==  methyl,  is  further- 
more to  be  considered  a  radical  or  complex  element, 
such  as  (NO3),  (SO4);  only  with  the  difference  that 


CARBON    COMPOUNDS.  303 

this  radical  is  of  a  positive  or  metallic  character. 
It  replaces  hydrogen.  Every  elementary  molecule 
is  composed  of  at  least  two  atoms.  That  is,  hydro- 
gen in  the  free  state  is  not  H  but  H2  ;  chlorine  not 
Cl  but  Cl2.  Then  in  the  hydrogen  molecule  H-H 
we  can  replace  1H  by  (CH3)  as  its  equivalent. 


+  (CH3)  =  =  +  H  ==  CH4  +  H. 

Or,  again,  H2(S04)+2(CH3)H=2(CH3).(S04)+4H; 
the  latter  compound  is  then  methyl  sulfate,  same  as 
sodium  sulfate.  In  ethane  C2H6,  the  older  concep- 
tion saw  the  radical  ethyl  C2H5  united  to  1  hydro- 
gen. But  it  is  simpler  to  think  of  it  as  a  coalescence 
of  2  methyl  groups. 


Propane,  C*H*  =  (C*H1).H=propyl  hydrid  = 

CH3.CH2.CH3. 

Two  methyl  groups  joined  by  CH2  which  latter  is 
the  lowest  member  of  the  series  CnH2n. 

Butane,  C*Hl(>  =  (C*H»)H=  butyl  hydrid,  But 
on  the  methyl  hypothesis  there  will  be  two  combi- 
nations, which  have  been  actually  proved  to  exist, 
two  bodies  having  exactly  the  same  percentage  com- 
position, but  distinct  properties,  to  wit  : 

CH3.CH2.CH2.CH3,  normal  butane;  and 

CH3 

CH^CH3,  iso-butane. 
XCH3 

Such  bodies  as  these,  of  equal  atomic  or  percentage 
composition,  are  called  isomerids.  Isobutane  is  the 
isomerdi  of  butane. 


304  CHEMISTRY    SIMPLIFIED. 

For  pentane  C5H12  there  are  three  isomerids  : 
CH3.CH2.CH2.CH2.CH3,  normal  pentane. 

CH3 

CH^CH3  ,  di-methyl-ethyl-m ethane, 

X(CH2.CH8) 

CH3>  C  "^CH3'  tetra-methyl-methane. 
In  the  last  we  imagine  a  marsh  gas  molecule 
H         H 

>C\ 
H         H 

in  which  every  hydrogen  atom  has  become  replaced 
or  substituted  by  the  methyl  group.  The  second 
isomerid  can  be  represented,  to  show  the  similarity, 
thus 

H-       CH3 

\Q/ 

CH3/   XCH2.CH3. 

I  beg  to  remind  you  that  this  so-called  structural 
representation  is  not  to  mean  a  real  picture — for  in 
reality  we  have  to  deal  with  three  dimensions,  not 
with  two  as  on  this  sheet  of  paper.  This  is  an  at- 
tempt to  express  symbolically  the  difference  in 
properties  of  the  isomeric  bodies. 

In  the  light  of  this  exposition  on  marsh  gas,  we 
will  reconsider  the  wood  alcohol  and  the  acetic  acid. 
For  the  wood  alcohol  we  had  the  atomic  proportion 
CH40,  it  being  then  suggested  that  this  formula  may 
be  written  CH3(HO),  and  now  we  see  that  the  methyl 
alcohol  is  a  marsh  gas  in  which  1  H  is  replaced  by 
the  radical  (HO)  hydroxyl. 


CAKBON    COMPOUNDS.  305 

H         H 


,  methyl  alcohol,  hydroxyl  methane. 
H 


For  acetic  acid  H.C2H302  we  can  write 

FT  TT 

"  \Q/  >  acetic  acid,  hydroxyl-carbonyl 

H7  \X).OH          ^ethane. 

The  group  CO.  OH,  carbonyl-hydroxyl,  is  mono- 
valent  ;  by  the  entering  of  this  group  into  a  hydro- 
carbon, the  latter  takes  on  the  properties  of  an  acid. 
The  lowest  form  is  formic  acid  (ant  acid)  CHO*.H 
which  is  found  with  the  acetic  acid.  Here  we  can 
say  that  the  group  CO.  OH  is  simply  coupled  with 
one  H. 

WOOD  OR  CELLULOSE  UNDER  PRESSURE  AND  HEAT. 

If  compressed  cotton,  or  a  stick  of  dry  wood,  or 
dry  sawdust  be  enclosed  in  a  strong  glass  tube  as 
shown  at  Fig.  89,  A  in  figure  1,  and  if  the  tube 

FIG.  89. 


C  W  /////////////////////  //\ 

t 

A 


be  then  fused  together  as  at  C,  figure  2,  over  a  blast 
lamp  and  the  part  D  be  pulled  off,  the  wood  A  will 
20 


306 


CHEMISTRY    SIMPLIFIED. 


be  enclosed  air-tight  as  in  figure  3.  Care  must  be 
had  that  the  wall  of  the  tube  remains  throughout  of 
even  thickness.  If  this  tube  be  then  placed  within  an 
air-bath,  and  the  temperature  be  gradually  raised 
to  320°  C.  as  indicated  by  the  air  thermometer, 
Fig.  90,  then  it  is  evident  that  the  distillation  of  the 


FIG.  91. 


wood  proceeds  under  increasing  pressure  :  First,  by 
the  expansion  of  the  air ;  second,  by  the  expansion 
of  the  gases  and  vapors  which  arise  from  the  wood 
at  this  temperature.  Let  the  condition  of  things 
remain  thus- for  twenty-four  hours.  Let  cool  slowly. 
On  examining  the  tube  we  find  the  wood  converted 
into  a  jet-black  shining  mass ;  the  cellulose  structure 
is  effaced  altogether  and  the  resemblance  to  soft  coal 
is  unmistakable.  We  open  the  tube  very  cautiously 
(after  taking  its  weight)  as  follows :  Since  the  pres- 
sure is  still  high  (presumably)  a  sudden  breaking 


CARBON   COMPOUNDS.  307 

of  the  tube  might  have  a  very  shattering  effect  (like 
a  boiler  explosion).  Therefore,  we  approach  the 
pointed  end  of  the  tube  to  a  strong  flame,  as  shown 
in  Fig.  91.  In  measure  as  the  glass  nears  red  heat, 
it  will  become  soft,  and  expand  under  the  interior 
pressure  until  at  the  very  tip  it  will  be  blown  out, 
giving  vent  to  the  compressed  gases.  On  weighing 
the  tube,  now,  it  is  found  that  about  2  per  cent,  of 
the  weight  of  the  wood  has  disappeared,  that  much 
having  been  converted  into  permanent  gas.  Now 
we  wash  carefully  the  mass  in  the  tube  by  means  of 
alcohol  (to  dissolve  any  tar-stuff),  and  after  drying 
in  a  current  of  dry  air,  find  again  a  diminution  in 
the  weight  of  about  3  to  4  per  cent.  Altogether 
about  20  per  cent,  in  weight  of  the  cellulose  has 
vanished.  The  importance  of  this  experiment  will 
appear  in  the  next  section. 


CHAPTER  XVI. 

MINERAL  COAL  AND  ITS  CHEMISTRY. 

WITHOUT  mineral  coal  the  industrial  development 
of  modern  times  would  have  been  impossible.  Some 
250  millions  of  tons  are  now  mined  annually  in  the 
United  States,  much  more  than  all  the  other  minerals 
together.  The  conditions  under  which  coal  is  found, 
and  its  association  with  other  rocks,  form  a  subject  of 
stratigraphic  geology.  The  points  to  which  your  at- 
tention is  here  called  refer  to  the  properties  of  coal 
and  the  uses  to  -which  coal  can  be  and  is  applied 
owing  to  such  properties. 

We  distinguish  (1).  Hard  coal  or  anthracite. 
(Greek  anthras  =  coal.)  Color  intensely  black,  luster 
more  or  less  bright.  Fracture  smooth  and  spheroi- 
dal. Hardness  considerable ;  the  pick  does  not  pro- 
duce much  effect ;  drilling  and  blasting  is  necessary. 

(2).  Soft  coal,  bituminous  coal,  semi-bituminous, 
blacksmith  coal.  Much  softer  than  anthracite,  color 
black,  but  color  of  fine  powder  is  brown.  Cleaves  or 
breaks  into  prismatic  pieces.  When  heated  in  glass 
tube  gives  off  dense  yellow  vapors  which  separate  into 
a  liquid  and  into  a  combustible  gas,  whereas  anthra- 
cite gives  off  no  vapors,  and  only  very  little  gas.  If 
the  coal  melts  into  a  black,  thick  liquid,  it  is  called 
bituminous  (bitumen  being  the  Greek  word  for  the 
(308) 


MINERAL    COAL    AND    ITS    CHEMISTRY.  309 

natural  pitch  also  known  as  asphaltum).  If  the  coal 
merely  softens  in  the  heat,  does  not  become  quite 
liquid,  then  we  call  it  semi-bituminous,  (half  pitchy). 

(3).  Cannel  coal,  has  a  black  color  but  differs  by 
absence  of  luster  from  the  ofher  varieties.  It  breaks 
with  an  irregular  surface.  When  heated  it  does  not 
melt  nor  become  soft,  but  yields  both  condensible 
vapors  and  bright  burning  gas .  in  abundance,  (can- 
nel  is  the  Scotch  of  candle).  This  coal  is  not  as 
abundant  as  the  other  varieties  and  is  of  higher 
value,  because  it  furnishes  a  larger  volume  of  illumi- 
nating gas.  It  is  only  used  for  gas-making. 

(4)-  Brown  coal,  lignite.  Dark-brown  color,  dull 
in  appearance,  very  soft,  can  be  shoveled  from  the 
pit,  shows  the  cell  structure  of  wood  and  hence  the 
name  lignite  (lignum  =  wood).  When  heated  it  does 
not  soften,  but  gives  gas  and  tar,  although  less  of 
these  than  cannel  coal ;  and  more  water.  It  is  usu- 
ally mixed  with  sand  and  clay  to  a  much  larger  ex- 
tent than  the  other  coals.  The  beds  lie  near  the 
surface,  that  is,  they  belong  to  more  recent  geological 
times.  Very  abundant  all  over  Western  United 
States,  Central  Europe,  Asia  and  Africa.  The  cities 
of  Northern  Germany  use  this  material  exclusively 
for  fuel,  on  account  of  its  cheapness. 

(5).  Peat,  bog,  turf.  Brown  or  brown-black  in 
color,  very  loose  in  structure  and  crumbly.  Acts 
like  brown  coal,  when  heated  after  having  been 
dried.  This  material  is  found  always  in  flat  regions, 
where  the  water  cannot  drain  off  and  where  no 
grasses  can  grow  on  account  of  the  wetness.  But 


310  CHEMISTRY    SIMPLIFIED. 

on  the  other  hand,  the  different  varieties  of  mosses 
and  algae  develop  and  grow  with  astonishing  rapid- 
ity, one  generation  on  top  of  the  other,  each  genera- 
tion being  very  short-lived.  Being  so  near  the  air 
the  dead  mosses  undergo  a  partial  rotting  with  the 
formation  of  marsh  gas  and  carbon  dioxyd.  There 
are  bogs  known  to  be  50  feet  thick  and  more.  Ordi- 
narily they  do  not  exceed  3  feet  in  thickness.  Yet 
they  furnish  to  many  localities  their  only  fuel — Ire- 
land, Holland,  North  Germany  near  the  sea.  The 
higher  land  of  Western  New  York,  where  the  Hudson, 
the  Alleghany,  and  the  Delaware  rivers  have  their 
beginning,  contains  many  peat  bogs,  which  are  more 
or  less  utilized.  On  the  flat  tops  of  very  high  moun- 
tains such  bogs  have  been  found.  By  a  washing  pro- 
cess the  peat  substance  can  be  somewhat  freed  from 
the  sand,  and  it  can  then  be  converted  into  cakes  by 
pressing.  Such  cakes,  when  quite  air-dry  will  give 
a  hotter  fire  than  wood,  weight  for  weight. 

Composition  of  coal.  We  find  the  ultimate  or  ele- 
mentary composition  by  the  same  procedure  which 
we  followed  with  the  cellulose.  We  burn  a  known 
weight,  W,  with  copper  oxyd  and  oxygen  gas  and 
collect  the  products  of  the  combustion,  conveniently 
for  measuring  or  weighing.  We  find  invariably 
the  same  elements  to  wit :  Carbon,  hydrogen,  oxy- 
gen, nitrogen,  sulfur.  The  two  latter  are  not  in 
cellulose,  but  they  are  found  in  other  parts  of  plant 
structure.  Nitrogen  is  always  contained  in  the  pro- 
toplasm, and  sulfur  sometimes ;  without  the  proto- 
plasm no  plant  can  develop — it  is  the  blood  of  plant 


MINERAL    COAL    AND    ITS    CHEMISTRY.  311 

life.  The  seeds  of  plants  always  contain  much  nitro- 
gen (15  to  17  per  cent.).  Coal  contains  from  1  to  3 
per  cent,  of  nitrogen.  The  sulfur  varies  between 
wider  limits.  The  sulfur  can  be  in  union  with  the 
carbon  and  the  hydrogen,  and  is  then  invisible;  or 
combined  with  iron  as  yellow  pyrite,  and  is  then 
readily  visible. 

Coal  always  leaves  a  residue  after  the  carbon 
and  hydrogen  have  been  volatilized  by  oxidation 
into  CO2  and  IPO.  The  residue  is  called  ashes,' 
because  wood  leaves  ashes.  The  two  kinds  of  ashes 
are  very  unlike.  From  coal  ashes  water  does  not 
extract  potash,  nor  any  other  body ;  coal  ashes  are 
quite  insoluble ;  no  alkaline  reaction  whatever. 
Neither  HC1  nor  HNO3  nor  H2S04  dissolve  it,  only 
HF.  The  ashes  in  fact  contain  chiefly  the  oxyds 
of  silicon  and  aluminum  SiO2,  A1203,  and  Fe203 
when  the  ashes  have  a  brown  color.  The  clinker- 
ing  or  semi-fusion  of  the  coal  ashes  is  due  to  Fe203 
which  acts  as  a  flux  upon  the  other  oxyds ;  white 
coal  ashes  never  show  clinkering.  The  following 
analysis,  made  by  me  lately,  gives  the  ultimate 
composition  of  a  soft  coal  from  Kansas.  Carbon  = 
75.35,  hydrogen  =  5.50,  oxygen  and  nitrogen  = 
10.10,  sulfur -1.54,  SiO2  ==4.35,  A1203  =  2.70 
(being  together  ashes  equal  7.05,  snow  white)  mois- 
ture =0.45. 

Notice  the  total  absence  of  iron  oxyd,  whence  it 
follows  that  the  sulfur  must  be  combined  with  the 
carbon  and  hydrogen.  This  coal  belongs  to  the 
semi-bituminous  variety  verging  upon  cannel ;  for 


312  CHEMISTRY    SIMPLIFIED. 

the  residue  merely  adheres  slightly  after  having 
been  exposed  to  a  high  yellow  heat,  and  like  cannel 
it  has  a  dull,  black  color ;  powder  brown. 

The  proximate  composition  of  the  different  varieties 
is  but  imperfectly  known,  or  rather  guessed  at.  I 
mean  by  proximate  composition  the  molecular 
structure — the  manner  of  combination  of  the  ele- 
ments. You  can  do  no  better  than  to  imagine  the 
coal  to  be  an  intimate  mixture  of  solid  hydrocar- 
bons, oxy-hydrocarbons,  sulfo-hydrocarbons,  nitro- 
hydrocarbons,  amorphous  carbon,  and  mineral  par- 
ticles constituting  the  ash.  The  different  varieties 
of  hard  and  soft  coal  arise  from  the  preponderance 
of  one  or  more  of  the  above  groups  of  molecules. 
Reasons  for  this  hypothesis  are  :  (1)  The  crystalline 
structure  of  the  coal,  revealed  in  thin  translucent 
plates  or  sections  under  the  microscope  ;  (2)  The 
actions  of  solvents  upon  the  coal,  such  as  ether, 
benzole,  carbon  disulfid,  potassium  or  sodium  hy- 
droxyds. 

Origin  of  coals.  That  cellulose  is  the  original 
material  there  is  no  reason  to  doubt ;  all  hypotheses 
or  theories  start  with  this  base.  Generally,  how- 
ever, geologists  assume  that  the  material  for  the 
coal  beds  consists  in  the  successive  growth  of  tropi- 
cal forests  one  on  top  of  the  other.  My  own  theory 
differs  from  this.  The  chief  reasons  are  that  in 
many  places  we  find  trees  standing  upright  in  the 
coal  beds,  reaching  even  into  the  sandstone  or  slate 
strata  lying  over  the  coal  bed  as  shown  in  Fig.  92. 
Here  a  section  is  reproduced  from  an  English  coal 


MINERAL    COAL    AND    ITS    CHEMISTRY. 


313 


mine,  a  is  limestone,  b  is  fire-clay  (under  clay),  cc 
the  lower  and  upper  benches  of  a  coal  seam,  e  black 
coal  slate,  /  sandstone,  g  brown  slate,  tit  are  fossil 
trees,  whose  bark  is  also  coal,  but  whose  interior  is 
sandstone,  because  these  trees  belonged  to  the  class 
of  giant  reeds,  calamites  lepidodendron,  sigillaria, 
etc.,  and  therefore  contained  a  pithy  interior  and  a 
very  strong  fibrous  rind,  very  resisting  to  chemical 
change,  d  is  a  band  of  slate  separating  the  coal- 


bed  into  the  two  benches.  The  strata  a  and  b  were 
in  horizontal  position  during  the  coal-forming  times 
and  the  conditions  of  level  equal  to  that  of  very 
shallow  basins  very  near  the  sea  level ;  that  is,  the 
general  conditions  were  those  of  a  tropical  swamp 
as  we  find  them  in  our  time  along  the  Amazon 
River  in  South  America.  At  first  these  conditions 
were  favorable  to  the  growth  of  the  great  ferns  and 
the  gigantic  reeds.  Later  on,  the  land  sinking  very 
slowly,  the  swamp  became  too  wet  for  this  vegeta- 
tion and  in  its  stead  algae — the  lowest  type  of  plant 
life — which  you  find  always  in  the  shallow  pools  of 


314  CHEMISTRY    SIMPLIFIED. 

our  present  swamp  woods,  the  green  and  brown 
threads  began  to  flourish  abundantly,  luxuriantly. 
An  alga  is  a  plant  consisting  of  one  cell  or  of  an 
aggregate  of  cells,  of  which  however  each  cell  re- 
mains a  life  unit.  Each  cell  has  a  thin  wall  of  cel- 
lulose enclosing  a  liquid  interior  in  which  there  is 
a  floating  patch  of  protoplasm,  the  cell-nucleus  or 
cell-kernel.  While  these  generations  of  very  rapidly 
growing  cells  died  and  accumulated  on  the  bottom 
of  the  pool,  or  rather  upon  their  dead  predecessors, 
and  being  under  water  could  not  rot,  the  rivers  or 
creeks  emptying  from  higher  ground  into  the 
swamps  brought  the  fine  sand  and  clay  which 
settles  very  slowly,  as  you  well  know  from  the  rivers 
remaining  turbid  long  after  a  freshet.  In  time  this 
material — the  silt — settles  and  mixes  with  the  vege- 
table ooze,  and  there  we  .have  an  explanation  of  the 
intimate  admixture  of  the  ash  particles  with  the 
coal,  and  also  an  explanation  of  the  strong  varia- 
tion of  the  ash  percentage  in  the  different  parts  of 
a  coal  bed.  Whenever  a  slate  band  occurs  in  the 
coal,  according  to  this  theory,  we  presume  that  an 
unusual  freshet  carried  the  silt  faster  into  the  basin 
than  the  algae  could  accumulate,  in  fact  the  muddi- 
ness  interfering  with  rapid  growth.  The  silt  also 
settled  into  the  hollow  trunks  of  the  trees,  thus  pre- 
serving them  against  collapse  by  external  pressure. 
My  theory  of  the  algae  accounts  also  for  the  high 
percentage  of  nitrogen,  which  we  find  in  the  coal, 
because  the  relative  percentage  of  protoplasm  to 
cellulose  or  of  nitrogenous  substance,  is  larger  in 


MINERAL    COAL    AND    ITS    CHEMISTRY.  315 

the  algae  than  in  the  complex  cell-structures  of  trees. 
During  the  accumulation  of  the  ooze  a  decomposi- 
tion of  the  dead  algae  cells  began  to  set  in,  alike  to 
that  which  we  now-a-days  observe  in  the  peat  bogs, 
by  which  the  percentage  of  carbon  in  the  residue 
steadily  increases,  while  hydrogen  ^and  oxygen, 
notably  the  latter,  decrease :  CO2  forming  and  CH4 
and  IPO.  At  last,  the  ground  sinking  more 
rapidly,  the  influx  of  silt  increases  and  the  vegeta- 
tion stops,  the  sea  finally  encroaches  upon  the 
swamp  and  the  materials  for  sandstone  or  limestone 
are  brought  in.  They  cause  a  steadily  increasing 
pressure,  under  the  influence  of  which  internal  heat 
arises,  which  cannot  dissipate  as  the  rocks  are  very 
bad  conductors  of  heat.  Thus  the  plant  material 
comes  gradually  under  the  conditions  of  the  experi- 
ment upon  cellulose,  described  a  few  pages  back. 
Wherever  the  pressure  was  greatest  the  change 
towards  carbon  was  greatest.  Thus  we  find  in  East- 
ern Pennsylvania  only  anthracite  with  90-94  per 
cent,  of  carbon,  because  the  side  pressure  upon  the 
strata  was  so  great,  that  the  latter  became  greatly 
bent  and  even  doubled  upon  themselves  as  shown 
in  Fig.  93,  whilst  in  the  Western  States  the  strata 
remained  in  their  original  horizontal  position,  as 
seen  in  Fig.  94,  except  in  Colorado,  and  hence  we 
find  anthracite  in  the  latter  state.  The  dotted  lines 
in  Fig.  93  denote  that  part  of  the  coal  bed  which 
has  been  removed  and  lost  by  surface  destruction 
and  the  forming  of  the  present  topographical  out- 
lines. All  the  details  of  the  structure  of  the  coal 


316  CHEMISTRY    SIMPLIFIED. 

measures  belong  to  geology  ;  only  sufficient  had  to 


FIG.  94. 


V 


be  introduced  here  to  make  the  chemical  theory 
intelligible. 

DISTILLATION  OF    COAL COKING  PROCESS. 

By  distillation  of  cellulose — or  wood — we  ob- 
tained charcoal,  tar,  pyroligneous  acid,  CO,  CO2, 
CH4,  H  ;  and  since  coal  is  derived  from  cellulose 


MINERAL    COAL    AND    ITS    CHEMISTRY.  317 

we  may  and  should  expect  similar,  if  not  identical, 
products.  In  order  to  test  this  proposition  we  rig 
up  the  set  of  apparatus,  Fig.  76,  page  275.  The 
tube  Twe  charge  with  the  coarsely-powdered  coal, 
so  that  when  the  tube  lies  in  horizontal  position 
and  has  been  tapped  upon,  the  coal  only  fills  one- 
half  of  the  tube.  Why  ?  Because  at  red  heat  the 
bituminous  and  semi-bituminous  coals  swell  up, 
thus  clogging  the  tube  to  the  escaping  gas,  which 
latter,  with  increasing  pressure,  will  invariably 
break  the  tube.  We  Mart  heating  at  the  front  by 
using  the  diaphragm  or  shield  S.  First  we  note  a 
heavy  yellow  vapor,  from  this  condenses  a  brown 
liquid  in  the  receiver  3,  and  the  bell  B  fills  itself 
with  gas.  The  first  portion  of  gas  we  allow  to 
escape,  because  it  is  mixed  with  the  air  in  T  and  3. 
Anthracite  gives  no  vapor,  no  condensing  tar,  only 
a  relatively  small  volume  of  gas ;  because  anthra- 
cite has  already  undergone  the  distillation  under 
the  influence  of  great  pressure.  When,  at  bright 
red  heat,  the  evolution  of  gas  becomes  very  slow,  or 
stops  altogether,  we  disconnect  the  receiver  3  from 
T  and  B  from  3.  We  pull  the  tube  T  from  the 
furnace,  let  it  become  cool,  and  then  break  the  tube. 
We  find  the  residue  more  or  less  bright,  porous,  dark 
or  light  grey  in  color.  With  large  pores  the  stuff 
is  more  or  less  friable,  with  small  pores  it  becomes 
hard  and  tough.  For  bituminous  and  semi-bitum- 
inous coals  the  weight  of  the  residue  is  from  50  to 
65  per  cent,  of  the  original  weight  of  the  coal. 
The  technical  name  of  this  residue  is  coke,  which 


318  CHEMISTRY    SIMPLIFIED. 

word  is  derived  from  to  cook,  and  may  have  been 
merely  a  provincial  substitute  for  cake.  When 
brought  up  to  a  red  heat  in  a  current  of  air  the 
coke  burns  without  making  a  visible  flame,  although 
it  still  contains  a  remnant  of  hydrogen  and  oxygen, 
for  the  complete  change  of  coal  to  carbon  depends 
upon  the  temperature  and  time.  At  a  white  heat 
(in  fire-clay  crucible),  the  last  remnant  of  hydrogen 
can  be  eliminated.  The  ordinary  coke  is,  therefore, 
a  mixture  of  the  ashes  with  carbon  (amorphous 
and  also  graphitic),  and  more  or  less  hydrocarbon. 

Coke  is  required  as  fuel  in  blast  furnace  work,  es- 
pecially in  the  high-stack-furnaces  for  the  reduction 
of  iron  ores.  Why  ?  Because  if  coal  were  used,  the 
latter  would  convert  itself  into  coke  in  the  furnace, 
would  cause  a  loss  of  heat  energy  (elimination  and 
decomposition  of  the  hydrocarbons  and  oxy-hydro- 
carbons  requires  heat  addition  from  outside  sources), 
and  the  coke  thus  forming  would  cement  the  pieces 
of  ore  and  flux  into  a  solid  cake,  through  which  the 
large  quantities  of  nitrogen  and  carbon  monoxyd 
are  blown  in  at  the  bottom  of  the  furnace  could  not 
pass — the  furnace  would  clog  or  choke  and  event- 
ually extinguish  itself. 

For  this  need  of  the  blast  furnaces,  immense  quan- 
tities of  coal  are  converted  into  coke.  The  appara- 
tus for  making  coke  is  known  as  coke  oven,  not  kiln 
or  furnace,  but  oven.  Why  ?  Because  the  first  coke 
was  made  in  Dutch  bake-ovens.  The  so-called  bee- 
hive coke  oven  of  the  present  time  is  merely  a  slightly 
modified  bake-oven.  In  this  oven  all  the  gas  and 


MINERAL   COAL    AND    ITS   CHEMISTRY.         319 

the  tar  are  wasted.  In  the  scientifically  constructed 
ovens,  the  gas  and  tar  are  utilized.  Different  ovens 
have  been  constructed  in  Europe  in  great  profusion. 
Those  mostly  used  now  are  the  Solvay  oven,  and 
the  Hoffman  oven ;  they  have  also  been  intro- 
duced into  the  United  States.  The  detail  of  coke- 
making  belongs  to  metallurgy.  We  ttfrn  now  to  the 
contents  of  the  receiver  (3).  As  in  the  distillation 
of  wood  we  find  two  liquids,  one  oily  the  so-called 
coal  tar,  one  watery  of  light-brown  color.  This 
watery  liquid  smells  of  ammonia,  and  turns  red  litmus 
paper  blue.  Thus  it  is  the  reverse  of  pyroligneous 
acid  from  wood  distillation.  Addition  of  acid  to 
the  ammonia  water  produces  effervescence  :  CO2, 
H2S  are  given  off,  hence  the  water  contains  am- 
monium carbonate  and  ammonium  sulfid.  The 
occurrence  of  the  ammonia  proves  the  presence  of 
nitrogen  in  the  coal.  The  absence  of  the  acetic  acid 
may  be  explained  from  the  smaller  percentage  of 
oxygen  in  the  coal  and  from  the  higher  temperature 
needed  to  break  up  the  coal,  a  temperature  at  which 
C2H302.H  breaks  up  into  CH4  +  CO2.  The  princi- 
pal market  for  ammonia  being  that  as  fertilizer,  the 
cheapest  way  of  extracting  the  former  is  to  convert 
it  into  sulfate.  The  water  is  neutralized  with 
H2S04  and  the  solution  evaporated  by  means 
of  the  waste  heat  from  the  ovens.  The  result  is 
dark-brown,  crude  sulfate.  This  is  redissolved  in 
the  requisite  quantity  of  boiling  water,  filtered 
through  a  bed  of  charcoal  to  remove  the  tar  which 
separates  during  evaporation,  and  the  liquid  is  run 


320  CHEMISTRY    SIMPLIFIED. 

into  flat  basins,  where  the  sulfate  crystallizes  on 
cooling.  This  second  product  is  still  yellowish,  but 
good  enough  for  the  market. 

The  coal  tar,  the  oily  portion  of  the  condensed 
vapors,  is  composed  essentially  like  the  wood-tar. 
But  certain  valuable  hydrocarbons  are  contained  in 
the  coal  tar  in  larger  percentage.  These  hydrocar- 
bons are:  benzol  (C6H6),  toluol  (C7H8),  phenol 
(C6H5(OH)),  naphthaline  (C10H8),  anthracene 
(C14H10).  When  the  tar  is  subjected  to  distillation, 
light  oils  pass  over  first  up  to  a  temperature  of  180° 
C.  Benzol,  toluol,  phenol  are  contained  in  this 
portion  ;  at  a  higher  temperature  oil  passes  over 
which  solidifies  on  cooling.  The  cooled  mass  can 
be  recrystallized  from  an  alcohol  solution,  or  it  may 
be  purified  by  sublimation.  In  this  purified  state 
it  forms  large  thin  crystals  in  form  of  plates  with 
the  luster  of  mother  of  pearl  and  a  strong  peculiar 
odor.  This  is  the  napthaline  of  trade  and  is  largely 
used  to  protect  woolen  and  fur  goods  against  insects  : 
moth  balls.  Only  the  oil  which  passes  over  between 
80°  and  100°  C.  is  used  for  the  manufacture  of  ben- 
zol. Between  100°  and  130°  C.  toluol  and  phenol 
with  some  benzol  pass  over.  Pure  benzol  is  a  color- 
less very  mobile  liquid ;  boils  at  82°  C.  and  crystal- 
lizes at  0°  C.  Specific  gravity  =  0.85. 

Nitrobenzol,  CGH5.NO'2.  Is  obtained  by  treating 
the  benzol  with  a  mixture  of  cone.  H2S04  and 
very  cone,  or  fuming  HNO3  in  cast-iron  cylinders, 
which  can  be  cooled  by  running  water,  because 
the  reaction  is  very  energetic ;  1  hydrogen  of  the 
C6H6  is  removed  as  water  and  nitrobenzol  results. 


MINERAL    COAL    AND    ITS    CHEMISTRY.  321 

C6H6  +  HNO3  =  C6H5N02  +  H20. 
Nitrobenzol  is  a  yellowish  heavy  oil  which  boils  at 
205°  C. ;  and  has  a  pleasant  odor  resembling  that  of 
the  oil  made  from  bitter  almonds.  If  an  excess  of 
HNO3  is  used  the  dinitrobenzol  C6H4(N02)2  results. 
Anilin,C6H7N.  A  small  quantity  of  this  highly 
interesting  substance  is  already  contained  in  the  tar. 
But  from  nitrobenzol  it  can  be  obtained  in  any  de- 
sired quantity.  Anilin  forms  a  colorless  liquid, 
diffracts  light  strongly,  has  a'peculiar  odor  and  burn- 
ing taste.  The  oil  bqils  at  182°  C.  and  solidifica- 
tion sets  in  at  8°  C.  Specific  gravity  ==  1.02.  Is 
very  slightly  soluble  in  cold  water,  more  so  in  boil- 
ing water,  but  quite  soluble  in  alcohol,  ether,  carbon 
disulfid,  and  coal  oil.  It  burns  with  a  very  smoky 
flame.  Is  very  poisonous.  Chemically  anilin  may 
be  considered  as  ammonia  in  which  1  H  has  been 
replaced  by  the  hydrocarbon  radical  phenyl  thus 

HI  (C»H')-| 

H  >N  =  ammonia.  H      >N  =  anilin. 

HJ  H     j 

Like  ammonia  it  unites  with  HC1  and  other  acids 
and  forms  salts  :  C6H5.H.HNHC1  =  anilin  chlorid. 
These  salts  are  mostly  easily  soluble  in  alcohol  and 
crystallize  readily.  Anilin  is  a  fine  example  of  a 
complex  base. 

Methylanilin  is  another  base,  arising  from  a  sec- 
ond hydrogen  being  replaced  by  methyl,  thus  : 

C6H5.H.H.N  +  CH3I  +  heat  =  (C6H5)(CH3).H.N 

+  HL 
21 


322  CHEMISTRY   SIMPLIFIED. 

This   body,  known  as    "  Mauve  de   Paris,"    colors 
silk  and  wool  a  fine  violet  color. 

Rosanilin,  fuchsin.  This  was  the  first  splendid 
dye-stuff  prepared  from  coal-tar  through  the  way  of 
anilin,  by  means  of  oxydation  ;  usually  As205  is 
used  as  the  oxydizing  agent.  100  parts  of  anilin 
oil  are  poured  slowly  into  150  parts  of  a  water-solu- 
tion holding  75  per  cent.  As205  in  an  iron  vessel 
with  stirring  apparatus.  The  temperature  is  raised 
and  kept  for  five  hours  at  182°  C.  Water  and  un- 
changed anilin  dissolve  during  this  period.  The 
semi-fluid  residue  has  a  bronze  color,  and  from  it 
the  dye-stuff  is  extracted  by  boiling  water,  filtered, 
under  pressure,  through  felt.  Solution  contains  the 
rosanilin  as  arseniate  and  the  As203  which  is  formed 
during  the  process  of  oxydation.  By  saturating 
the  solution  with  NaCl  (equal  in  weight  to  the  resi- 
due), the  hydrochlorid  of  rosanilin  forms  and 
Na2HAs04.  Red  crystals  fall  out,  in  measure,  as 
the  liquid  cools.  By  recrystallizing  this  first  pro- 
duct a. higher  grade  is  obtained.  The  red  crystals, 
being  the  chlorid  of  rosanilin,  are  known  in  the 
dye-works  as  fuchsin.  By  acting  on  the  water  solu- 
tion with  NaOH,  the  base  rosanilin  is  obtained  as  a 
white  precipitate,  which  becomes  intensely  red  in 
contact  with  any  acid.  The  composition  of  rosanilin 
isC20H19N3.  It  forms  thus: 


C7H7 
2     H 
H 


C6H5 
N  +     H 
H 


C6H 


N+30  = 


C7H7 


N3+3H20. 


The  30  are  furnished  by  As205  or  any  other  oxy- 


MINERAL   COAL   AND    ITS   CHEMISTRY. 

dizing  agent.  But  we  see  that  another  body  is  here 
contained,  the  toluidin,  besides  the  anilin.  Remem- 
bering, however,  that  the  raw  oil  contains  benzol 
and  toluol,  the  phenomenon  is  explained. 

The  crystals  of  fuchsin  are  green-golden  in  ap- 
pearance, like  a  brilliant  metal.  They  dissolve  in 
water  with  intense  red  color.  If  well  cleansed  silk 
or  wool  be  hung  in  such  a  solution,  the  liquid 
becomes  colorless  by  degrees,  all  the  coloring  fuchsin 
will  have  transferred  itself  to  the  fibre,  producing 
thereon  the  beautiful  red  tints  according  to  the 
quantity  transferred.  The  color  fixes  itself,  does 
not  require  a  mordant  or  fixing  agent. 

Mauvanilin,  (C«H5)(C6H5)(C7H7)N*.HCl  gives  an 
orange-yellow  dye.  A  great  many  other  beautiful 
dye-stuffs  have  been  produced  by  further  substitu- 
tion of  hydrogen  in  the  base  by  other  radicals,  as 
anilin,  toluidin,  or  simply  methyl,  ethyl,  and  others. 
My  main  purpose  in  devoting  so  much, space  to  this 
subject  was  to  impress  upon  you  the  possibilities 
lying  hidden  in  such  a  material  as  the  ugly,  bad- 
smelling  coal-tar,  and  the  great  fortunes  which  have 
been  made  by  utilizing  it  in  the  right  way. 


CHAPTER  XVII. 

THE  GASES  FROM  THE  DISTILLATION  OF  COAL- 
MANUFACTURE  OF  ILLUMINATING 
GAS  AND  GAS  COKE. 

The  contents  of  the  bell  jar  are  at  first  cloudy 
from  exceedingly  small  particles  of  semiliquid  bodies, 
which  will  condense  after  a  time,  forming  a  thin 
layer  of  tar  upon  the  retaining  water  surface.  If 
now  the  gases  be  subjected  to  the  analysis  by  ab- 
sorption which  has  been  given  in  detail  under  cel- 
lulose or  wood,  it  will  be  found  that  the  composi- 
tion by  quality  does  not  differ  much  ;  the  relative 
quantities  differ  considerably,  and  even  very  much 
when  the  gas  from  the  early  distillation  is  compared 
with  that  which  is  given  off  at  the  end  of  the  opera- 
tion. We  find  H,  CH4,  CO,  CO2,  non  luminous : 
C2H4,  C3H6,  C4H8  and  C2H2,  (acetylene)  as  lumi- 
nous gases.  NH3,  SH2,  CS2,  CN  as  impurities. 

Of  the  luminous  or  light-producing  hydrocarbons 
ethylene  (C2H4)  olefiant  gas  (oil-making  gas)  is  the 
most  important;  of  propylene  (C3H  )  there  is  least ; 
of  butylene  C4H8  there  is  usually  from  J  to  J  as 
much  as  of  ethylene.  These  hydrocarbons  combine 
with  chlorine,  bromine  or  iodine,  thus : 

C2H4  +  2C1  =C2H4C12,  ethylene  chloride  oil-like 
liquid  (hence  the  name  olefiant  or  oil-making.) 
Spec.  Gr.  =  1.174. 

(324) 


GASES    FROM   THE    DISTILLATION    OF    COAL.       325 

At  red  heat  ethylene  breaks  up,  thus : 
C2H4  +  red  heat  =  C  +  CH4,  amorphous  carbon 
+  marsh  gas. 

It  is  this  action  which  we  call  dissociation,  that 
a'ccounts  for  the  smoking  of  a  gas  flame.  If  oxygen 
is  present  both  C  and  CH4  are  oxydized  to  2C02  + 
2H20.  Bromine  acts  like  chlorine  upon  ethylene: 
C2H4  +  2Br  =  C2H4Br2  an  oily  liquid  as  the  pre- 
ceding one.  Propylene  and  butylene  are  acted  upon 
similarly:  C3H6  +  2C1  =  C3H6C12;  C4H8  +  2C1  = 
C4H8C12,  propylene  chlorid,  butylene  chlorid. 
Hence  it  follows  that  we  can  remove  these  three 
gases  from  a  mixture  of  gases  by  shaking  the  mix- 
ture with  bromine  water  in  a  suitable  gas  pipette. 
The  higher  we  find  their  percentage  in  a  given  gas 
the  more  we  are  sure  of  a  bright  light,  provided 
that  the  burner  be  suitably  constructed. 

PLAN    FOR    GAS    WORKS. 

Figs.  95  and  95a  give  the  essential  pieces  of  ap- 
paratus for  the  production  of  illuminating  gas  by  dis- 
tillation of  coal,  in  ground  plan  and  length  elevation. 
R,  R',R2  represent  a  fire-brick  retort  and  ovens  for 
heating  them  to  a  yellow  heat.  H  is  a  sheet-iron  pipe 
18"  to  24"  in  diameter  and  known  as  the  "  hydraulic 
main."  The  elevation  shows  how  the  retort  con- 
nects by  a  goose-neck  pipe  with  this  main  and  also 
that  the  pipe  dips  under  the  water  level  of  the  main, 
thus  producing  a  light  pressure  upon  the  gas  in  the 
retort.  Most  of  the  condensible  constituents  of  the 
gas  become  liquid  in  contact  with  the  liquid  in  the 


FIG.  95. 


(326) 


(827) 


328  CHEMISTRY    SIMPLIFIED. 

pipes.  At  N  there  is  provided  an  overflow  which 
drains  into  a  vertical  tank  or  cistern  ;  thus  the  level 
remains  always  the  same  in  the  main.  Steam,  tar, 
ammonium  salts  are  condensed  largely.  A  pipe  C 
leads  from  top  of  main  to  the  purifying  towers 
S,S',S2  which  are  technically  known  as  scrubbers. 
S,Sf  are  wet  scrubbers,  because  the  gas  must  pass  the 
extensive  surface  of  the  horizontal  trays  over  which 
flows  a  film  of  cold  water.  All  the  ammonium 
compounds  and  all  the  tar  are  removed  from  the 
gas  in  these  wet  scrubbers,  but  the  gas  still  contains 
a  notable  quantity  of  hydrogen  sulfid.  The  latter  is 
taken  care  of  in  S2  which  is  a  dry  scrubber,  for 
here  the  trays  are  covered  each  with  a  layer  of 
Laming' s  mass,  to  wit :  a  mixture  of  Ca(HO)2  with 
FeSO4  +  7H20  (copperas).  Ca(HO)2  +  FeSO4  - 
CaSO4  -f  Fe(HO)2  ;  it  is  the  latter,  ferrous  hydroxyd, 
which  is  the  active  agent.  At  first  Ca(HO)2  (dry 
slaked  lime)  was  used  alone.  Ca(HO)2  +  EPS  = 
CaS  +  2H20.  But  the  action  is  slow.  When  the 
book-backs  in  the  public  libraries  of  London  and 
other  cities  began  to  crumble  away,  the  cause  was 
traced  to  the  gas  flames  and  more  specially  to  the 
sulfuric  oxyd  produced  by  them,  i.  e.,  by  the  burn- 
ing of  H2S  to  SO3.  Then  Laming  invented  the 
mixture  and  thus  checked  the  evil,  without  knock- 
ing it  out  altogether.  The  carbon  disulfid  CS2  has, 
so  far,  resisted  all  attempts  at  absorption  in  the 
scrubbers.  The  dry  scrubbers  must  be  provided  in 
duplicate  or  triplicate,  because  they  need  frequent 
renewing  of  the  Laming  mixture,  which  becomes 


GASES    FROM    THE    DISTILLATION    OF    COAL.       329 

foul  as  the  men  say.  The  gas  is  now  ready  to  flow 
through  the  pipe  Cf"  into  the  holder  G.  The 
holder  is  a  sheet-iron  tank  of  circular  or  cylindrical 
shape.  It  is  closed  at  the  upper  end  and  dips  with 
the  open  lower  end  into  water  of  the  walled  and 
cemented  cistern  C.  The  tank  G  is  held  in  place 
by  6  or  more  guide  rolls,  and  is  counterbalanced 
by  the  6  weights  W,  W,  etc.  These  consist  of  cast 
iron  disks,  superposed,  so  that  the  bell  may  be  made 
to  press  upon  the  gas  at  any  pressure,  by  adding  or 
removing  a  disk,  from  each  or  to  each,  of  the  6 
weights.  By  adding  disks  the  bell  may  take  the 
function  of  a  suction  pump  thus  causing  the  gas  to 
overcome  the  friction  of  scrubbers,  during  the 
progress  of  the  distillation.  The  elevation  explains 
the  entrance  of  the  gas  at  in  and  the  outflow  at  out 
if  the  main  valve  V'  is  open.  This  valve  is  always 
accessible  through  the  pit  P.  The  dimensions  of 
the  plant  follow  from  the  rate  of  consumption  of  the 
gas.  As  one  15  candle-power  burner  consumes  5 
cubic  feet  of  gas  per  hour,  and  as  the  burners  are 
needed  on  the  darkest  day  for  8  hours,  and  as  each 
family  uses  on  the  average  4  burners,  we  get  160 
cubic  feet  per  family  per  day.  1000  families  require 
160,000  cubic  feet  +  10  per  cent,  for  street  lighting, 
total  176,000  cubic  feet,  hence  18  tons  of  coal  will 
be  required  per  day  giving  roughly  9  tons  of  coke. 
A  bell  30  feet  in  diameter  and  20  feet  high  will 
hold  16,000  cubic  feet.  Ten  such  would  be  required 
to  store  the  160,000  cubic  feet.  However  the  bell 
serves  more  as  a  regulator  than  as  a  storage.  The 


330  CHEMISTRY    SIMPLIFIED. 

retorts  are  kept  going  all  through  the  hours  of 
largest  consumption.  One  holder  is  sufficient  for 
each  1000  families.  Holders  of  100  feet  diameter 
and  25  feet  high  have  been  built  in  large  cities. 
The  retorts  are  made  of  fire-brick  material  and  have 
a  ^^  section.  They  are  5  to  6  feet  long,  18  to  24  in. 
wide  (inside),  12  to  15  inches  high.  Thickness  of 
bottom  3  to  4  inches,  of  sides  and  top  2J  to  3  inches. 
The  average  daily  capacity  per  retort  is  5000  cu. 
feet ;  hence  32  retorts  will  be  required  for  160,000 
cu.  ft.  daily  production.  The  retorts  are  best 
arranged  in  batteries  of  7  each  with  one  common 
fire-place. 

WATER-GAS. 

(a)  Water-Gas.  H20  +  C=H2-f-COat  yellow 
or  white  heat.  The  mixture  of  hydrogen  and  car- 
bon, monoxyd  burns  with  colorless  flame,  hence  the 
gas  must  be  made  luminous  by  the  addition  of 
gasoline  or  hydrocarbons  of  the  olefine  series. 
Prof.  Lowe  of  Norristown,  Pa.,  introduced  the  ap- 
plication of  this  reaction  into  the  gas  industry  about 
1873.  It  displaces'  the  distillation  process,  but  has 
not  been  introduced  in  many  gas  works  until  more 
recently  in  a  modified  form. 

The  action  H20  +  C=CO  +  H2is  endothermic, 
heat-consuming. 

The  action  C  +  20  =  CO2  is  exothermic,  heat- 
producing. 

Hence  the  process  of  preparing  water-gas  is 
necessarily  a  double  one,  Let  1,  2,  Fig.  96,  be  two 


GASES    FROM    THE    DISTILLATION    OF    COAL.       331 

fire-brick  cylinders  held  each  in  a  sheet-steel  mantle. 
Let  these  cylinders  stand  upon  iron  pillars,  10,  10. 
10,  which  will  enable  a  dropping  of  the  hinged 
bottoms,  3,  8,  and  thus  an  emptying  of  the  cylinders 
of  ashes  and  klinkers.  Let  the  cylinders  be  filled 
with  pieces  of  coke  or  charcoal.  At  4,  4  we  have 
charging  hoppers.  At  5,  5  air-pipes  enter  the 
cylinder,  and  at  6,  6,  steam-pipes.  At  7,  7  small 


pipes  can  introduce  coal-tar.  The  gas  passes  at  <?,  8 
into  the  common  pipe  9.  Before  charging  the  coke, 
small  wood  and  shavings  are  put  into  the  cylinders 
to  start  the  fire  with  in  one  cylinder  first.  Then 
compressed  air  is  allowed  to  enter  the  through  pipe 
5,  coke  is  charged  until  it  reaches  just  below  the  gas 
outlet  8,  and  the  valve  in  the  hopper  4,  is  left  open. 
Under  these  conditions,  a  gas  mixture  passes  out  from 
the  hopper,  which  is  composed  of  nitrogen,  chiefly 


332  '  CHEMISTRY    SIMPLIFIED. 

(60  per  cent,  to  70  per  cent),  carbon  dioxide  and 
carbon  monoxyd  (N  +  CO2  +  CO).  The  sum  of 
N  +  CO2  being  at  the  least  75  per  cent.,  it  follows 
that  this  gas  is  only  a  low-grade  heat-producer,  and 
is  therefore  allowed  to  escape  through  the  hopper. 
When  the  top  layer  of  coke  has  come  to  bright  red 
heat,  the  lower  layers  will  be  at  white  heat.  The 
hopper  valve  is  now  closed,  and  the  valve  at  8 
opened.  The  air  valve  in  5  is  closed,  and  the 
steain  valve  in  6  opened.  As  the  steam  impinges 
upon  the  white-hot  coke,  it  breaks  up  into  H2  +  CO. 
If  the  valve  in  the  tar  pipe  T  be  now  opened 
properly,  the  tar  will  fall  upon  the  bright  red  coke 
and  be  dissociated,  i.  c.,  the  higher  molecules  of 
CnHn,  CnH2n  and  CnH2n+2  will  be  broken  up  into 
the  lower  members  of  the  series,  into  carbon  and 
into  marsh-gas.  Read  again  what  is  said  about  this 
under  tar  and  the  distillation  of  coal.  All  these 
hydrocarbons  will  mix  with  the  main  mass  of 
hydrogen  plus  carbon  monoxyd,  will  pass  through 
pipe  9  into  the  gas  holder,  or  directly  to  the  burners, 
and  yield  a  fine  light,  or  if  more  air  be  allowed  to 
mix  with  the  gas  in  the  burner,  a  very  intense  heat, 
and  a  non-luminous  flame.  All  this  while  the 
white  heat  of  the  coke  drops  down  steadily  to  a  red 
heat  and  H20  can  be  no  longer  decomposed.  In 
common  language  we  say  that  the  steam  quenches 
the  fire,  i.  e.,  extinguishes  it.  But  the  second 
cylinder  has  been  brought  up  to  white  heat  during 
the  time.  We  shut  off  the  first  cylinder  from  pipe 
9}  open  the  valve  £  and  the  steam  valve,  repeating 


GASES    FROM    THE    DISTILLATION    OF    COAL.       333 

all  the  operations  as  before,  while  the  first  cylinder 
is  again  blown  to  white  heat — exchanging  the 
steam  for  air.  Thus  by  means  of  the  two  cylinders 
a  perfectly  steady  stream  of  water-gas  is  produced. 
A  battery  of  three  cylinders  is  more  advantageous 
still,  for  then  we  can  throw  out  one  after  another 
of  the  cylinders  for  the  purpose  of  removing  the 
ashes  and  klinkers  without  danger  of  explosion. 


FUEL— GAS. 


Under  this  name  goes  a  mixture  of  gases  of  in- 
ferior grade  to  the  water-gas ;  cheaper  correspond- 
ingly, and  much  in  use,  at  this  time,  in  metallurgi- 
cal works  and  also  for  the  feeding  of  gas-engines. 


Chemistry.  Steam  and  air  are  blown  into  the 
coke  simultaneously  ;  the  air  and  the  steam  periods 
of  the  water-gas  process  are  thrown  into  one  period. 
One  cylinder  only  is  required  for  the  same  volume 
of  gas  per  minute.  Let  Fig.  97  represent  the  sec- 


334 


CHEMISTRY   SIMPLIFIED. 


tion  plan  of  the  cylinder  in  the  level  of  the  steam 
pipe  6,  Fig.  96;  let  S,  Sl}  S2  be  the  three  steam 
pipes  and  i,  i,  i  the  parabolic  injectors  (system  of 
Koerting).  Then  there  will  be  sucked  up  by  the 
steam  jets  a  volume  of  air  depending  upon  the 
velocity  of  the  steam  (pressure)  and  upon  the  capa- 
city of  the  injector.  The  pressure  of  the  steam  must 
be  adjusted  to  the  capacity  of  the  injector  so  that  the 
exothermic  product  CO2  -+-  N4  is  larger  by  about 
i  than  the  endothermic  product  C  +  H20(CO  +  H2). 
The  i  over  energy  is  consumed  by  loss  of  heat 
through  conduction,  radiation  and  fusion  of  the 
ashes.  The  latter,  the  fusion  of  the  ashes,  can  not 
be  obtained  unless  a  proper  amount  of  CaO  be 
charged  with  the  coal  or  coke  and  the  percentage  of 

FIG.  98. 


each  as  well  as  the  composition  be  known.  A  lip 
or  outflow  must  be  provided  for  the  slag  as  shown 
in  Fig.  98,  where  1  is  the  slanting  bottom,  2  the 
dam  of  the  forehearth,  3  a  hollow  iron  beam, 
through  which  water  circulates  to  keep  open  the  out- 
flow and  prevent  the  eating  away  of  the  firebrick  ; 
4.  is  the  inner  level  of  the  liquid  slag ;  5  is  its  outer 
level  and  when  more  slag  comes  it  will  run  over  the 


GASES    FROM    THE    DISTILLATION    OF    COAL.       335 

dam  ;  6  is  the  twyer  or  opening  for  the  injector ;  7  is 
the  foundation.  If  raw  soft  coal  is  to  be  used  in  this 
fuel-gas  proposition,  the  cylinder  must  be  provided 
with  a  rotating  breaker,  to  prevent  the  forming  of 
cakes  and  lumps,  which  always  make  poor  gas. 

PETROLEUM,  ROCK-OIL,  MINERAL    OIL. 

The  term  coal-oil  is  most  used  in  the  United 
States.  It  is  nut  a  good  name  because  implying  a 
relationship  between  coal  and  this  oil.  Such  a  re- 
lationship has  not  been  proven  in  any  instance. 
All  the  Pennsylvania,  Ohio,  West  Virginia,  Indi- 
ana oil  comes  from  rocks  which  lie  under  the  coal 
measures,  very  much  older  in  order  of  formation. 
Rock-oil  is  a  perfectly  appropriate  term.  In  regard 
to  the  origin  of  the  oil  in  these  rocks,  the  most  plaus- 
ible opinion  is  that  of  Engler  who  ascribes  the  oil 
to  enormous  numbers  of  dead  fish  within  the  sand, 
which  now  forms  the  oil-carrying  strata.  Engler 
obtained  oils  very  similar  to  coal-oil  by  subjecting 
fish  to  great  pressure  at  temperatures  not  much 
above  the  boiling-point  of  water. 

Finding  of  the  oil.  Along  Oil  Creek,  Pa.,  the  oil 
was  found  but  50  feet  under  the  surface,  but  for  the 
most  part  the  oil  strata  are  buried  deeply.  The 
gushing  or  flowing  of  the  oil  from  a  fresh  hole  is 
due  to  the  accumulated  pressure  of  marsh  gas.  As 
this  pressure  becomes  released  the  automatic  flowing 
ceases,  and  pumping  becomes  necessary. 

Physical  properties  of  the  oil.  Most  oils  are  col- 
ored ;  they  appear  red  or  brown-red  in  transmitted 


336  CHEMISTRY    SIMPLIFIED. 

light  and  opalescent  green  in  reflected  light.  This 
double-color  or  dichroism  is  owing  to  the  presence  in 
the  oil  of  one  constituent  which  has  received  the 
proper  name :  fluorescin.  The  odor  is  very  strong 
and  characteristic.  Sometimes  the  crude  oil  is  quite 
mobile  and  sometimes  it  is  thickish,  viscous.  So 
also  varies  the  specific  gravity  from  0.75-0.95. 
None  has  yet  been  found  heavier  than  water.  The 
crude  oil  is  usually  quite  inflammable. 

Chemical  properties.  In  general  it  will  hold  true 
to  say  :  Petroleum  is  a  complex  liquid.  The  consti- 
tuting members  of  the  complex  are  hydrocarbons 
of  the  marsh  gas  or  paraffin  series  (CnH2n+2).  The 
individual  members  of  the  series  can  be  separated 
by  fractional  distillation  many  times  repeated  (see 
under  wood-tar  and  coal-tar).  The  members  from 
C4H10  to  C16H34  have  actually  been  prepared  by 
several  chemists.  The  density  of  the  liquid  and  its 
boiling-point  are  the  mean  of  those  constants  pro- 
portionately to  the  percentages  of  the  constituting 
hydrocarbons.  The  heat-value  of  coal-oil  is  very 
high,  much  higher  than  that  of  vegetable  and 
animal  fats,  because  oxygen  is  absent.  Some  crude 
oils,  however,  contain  sulfur  compounds.  Coal-oil 
cannot  be  saponified  by  NaHO  or  KHO,  and  by 
this  negative  property  we  distinguish  the  mineral 
oil  from  vegetable  or  animal  oil.  (See  further  on.) 

Refining  of  crude  oil.  The  crude  oil  is  stirred 
together  with  concentrated  sulfuric  acid.  By  this 
treatment  the  objectionable  sulfur  compounds  are 
converted  into  a  solid,  resinous  body  which  settles 


GASES    FROM   THE    DISTILLATION    OF    COAL.       337 

with  the  acid,  and  the  cleansed  oil  is  drawn  off.  The 
latter  is  then  subjected  to  the  action  of  steam  heat 
in  large  iron  tank-boilers,  and  later  on  to  direct  fire. 
Thus  are  obtained  the  conventional  fractions :  1. 
Petroleum  ether,  a  colorless,  very  mobile  oil  of  pleas- 
ant odor  and  intoxicating  effect,  passes  over  up  to 
70°  C.  This  oil  is  much  used  as  a  solvent  for  fats 
and  other  bodies.  2.  Gasoline  distills  between  70° 
C.  and  90°  C.  3.  Benzine  distills  over  between  90° 
C.  and  150°  C.  After  this  is  collected  4.  Kerosene 
between  150°  C.  and  300°  C.  This  portion  is  most 
valued  for  burning  in  lamps,  because  its  flash-point 
is  high  and  it  is  therefore  safe.  5.  Lubricating  oil 
distills  between  300°  C.  and  400°  C.  6.  Vaseline 
distills  next  and  condenses  as  a  semi-solid  in  the  re- 
ceiver. 7.  Beyond  this  comes  off  considerable 
paraffin,  a  perfect  solid  (see  under  tar);  a  black, 
spongy  residuum  remains  in  the  still. 

Determining  the  flash-point  of  a  given  coal-oil. 
Pour  the  oil  into  a  small  tin-cup,  which  stands  upon 
a  water  bath.  With  one  hand  hold  a  thermometer 
into  the  oil,  with  the  other  pass  a  lighted  match 
across  the  surface  of  the  oil.  Note  the  temperature 
of  the  oil  at  which  the  vapor  above  the  oil  catches 
fire.  This  temperature  is  known  as  the  flash-point 
and  should  not  be  below  60°  C.  for  a  safe  burning  oil. 

NATURAL  GAS. 

Any  bore-hole  which  is  driven  into  sedimentary 
rock-formation  can  be  expected  to  produce  gas,  pro- 
vided the  strata  have  not  been  disturbed  much  from 
22 


338  CHEMISTRY    SIMPLIFIED. 

their  original  horizontal  condition.  Natural  gas  has 
been  found  by  many  analyses  to  be  composed  chiefly 
of  marsh-gas  (CH4).  If  it  burns  with  a  sooty  flame 
then  there  are  some  of  the  higher  members  of  the 
paraffine  series  present,  each  as  C2H6,  C3H8  .  .  . 
Sometimes  there  is  free  hydrogen  present  and  in  rare 
instances  CO  has  been  found  with  the  marsh-gas. 


CHAPTER  XVIII. 

THE  HOMOLOGUES  OF  CELLULOSES-STARCH, 
DEXTRIN,  SUGARS. 

So  cunning  is  the  work  of  nature  that  extraordi- 
nary changes  are  constantly  brought  about  in  prop- 
erties with  apparently  tbe  same  material.  The  study 
of  a  wheat  grain  will  illustrate  this.  Fig.  99  repre- 

FIG.  99. 


sents  the  section  through  the  axis  of  the  grain  in 
magnified  dimensions.  Beginning  from  the  outside 
there  are  3  layers  of  small,  attached  cells  1,  2,  3.  J, 
2  epicarpium  or  skin,  colorless  cells.  3  the  endo- 
carpium  ;  these  cells  contain  a  yellow  coloring  mat- 
ter. 4-  the  embryo  membrane,  large  cells,  contain- 
ing the  nitrogenous  body  gluten,  vegetable  albumen. 
5  a  layer  of  amorphous  substance,  grey.  6  the  meal- 
kernel  made  up  of  large,  loose  cells,  and  these  cells 
(339) 


340  CHEMISTRY    SIMPLIFIED. 

are  filled  with  a  multitude  of  white  globules  which 
globules  constitute  what  is  known  as  starch.  7  is 
a  dark-colored  cell,  known  as  the  embryo  or  germ. 

When  such  a  wheat  grain  is  soaked  in  water  or 
kept  wrapt  in  a  wet  cloth  the  grain  swells  and  two 
sprouts  appear  at  8,  that  is,  the  vital  power  lying 
dormant  in  the  protoplasm  of  the  germ  cell  awakes 
in  presence  of  water.  Cell  upon  cell  is  shot  out- 
wards until  two  blades  of  grass  appear  above  the 
earth,  which  gradually  develop  into  a  full  plant. 
The  material  for  these  cells  was  drawn  from  the 
store  of  starch  and  albumen,  so  cunningly  provided 
within  the  reach  of  the  embryonic  cell  within  the 
grain — a  veritable  fodder-sack. 

The  starch,  amylum.  A  white,  very  finely  gran- 
ular substance.  Under  the  microscope  we  see 
spheroidal  granules  built  up  from  concentric  layers. 
Feels  soft  to  the  touch.  When  pure  has  neither 
taste  nor  smell.  Is  insoluble  in  cold  water.  Hot 
water  swells  the  granules  until  they  flow  together 
into  a  shapeless,  transparent  paste,  starch-paste. 
The  paste  dries  into  a  yellowish,  hard,  horn-like 
body.  The  paste  is  slightly  soluble  in  water,  giving 
a  clear  solution  upon  standing.  Starch  develops 
in  the  roots  of  certain  plants,  namely,  such  plants 
which  grow  from  the  root  just  as  well  as  from  a 
seed — potato,  arrow  root,  sago.  The  seed  grain  of 
Indian  corn  is  richer  in  starch  than  other  seed 
grains.  Hence  starch  is  made  from  either  corn  or 
potatoes.  The  corn  is  ground,  while  the  potatoes  are 
cut  into  a  pulp  by  rotating  knives,  after  a  thorough 


THE    HOMOLOGUES    OP    CELLULOSE.  341 

washing,  to  remove  adhering  soil  particles.  The 
pulp  becomes  milky  ;  the  milky  liquid  is  strained 
off  through  a  very  fine  hair  sieve.  The  sieve  retains 
the  cellulose  or  skin  portions,  and  also  the  gluten. 
The  milky  liquid  is  allowed  to  stand,  when  the 
white  starch  will  settle  to  the  bottom  and  is  col- 
lected after  drawing  off  the  water.  The  starch  only 
needs  drying  to  be  at  once  a  commercial  product. 

Chemical  properties  of  starch.  (1)  The  analysis 
(same  as  for  cellulose)  leads  to  the  ratio  C6H1006, 
that  is  to  say,  identical  with  cellulose.  Note  nature's 
trick  to  give  two  very  different  bodies  the  same 
composition.  Such  bodies  are  named  isomeric  bod- 
ies. (2)  A  solution  of  iodine  in  alcohol  or  in  water, 
solution  of  KI  colors  the  starch,  first  purplish-red, 
and  then  blue.  Heating  causes  the  color  to  fade, 
but  on  cooling  the  color  reappears.  Very  character- 
istic reaction  for  the  identification  of  starch.  (3) 
Starch  dissolves  in  cold,  concentrated  HNO3.  The 
addition  of  water  throws  out  a  white  precipitate,  a 
nitro-body  similar  to  gun-cotton,  but  non-explosive. 
Boiling  very  dilute  acid  (2-3  per  cent.)  changes  the 
starch  into  dextrin  and  finally  into  glucose.  The 
word  starch  (stark  =  strong  in  German,  because 
starch  paste  stiffens  tissues). 

Dextrin  (from  dexter  =  right-handed).  A  gum- 
like,  syrup-like  substance,  or  dry  granular.  Much 
used  in  place  of  gum  arabic  (postage  stamps,  envel- 
opes), because  cheaper  and  more  reliable.  It  forms 
from  starch,  either  by  heating  the  dry  starch  to  210° 
C.  or  by  moistening  the  starch  with  2  per  cent. 


342  CHEMISTRY    SIMPLIFIED. 

HNO3  solution,  and  then  heating  to  110°  C.  (best 
method),  or  by  boiling  starch  with  2  per  cent. 
H2S04  solution  until  the  resultant  liquid  does  not 
turn,  blue  with  iodine  solution.  Dextrin  is  C6H1005, 
the  same  as  starch  and  cellulose.  Another  isomeric 
form.  It  is  not  soluble  in  alcohol,  but  easily  soluble 
in  water,  rotates  plane  of  polarization  to  right. 

The  sugars.  These  are  bodies  formed  in  the  sap 
of  the  cells  of  certain  plants  ;  in  the  seeds  (grape, 
orange,  etc.) ;  in  the  stem  (cane,  sorghum,  sweet 
corn);  in  the  roots  (beets,  carrots).  "All  soluble  in 
water  ;  some  crystallize,  others  are  syrups ;  all  pos- 
sess a  more  or  less  sweet  taste. 

Cane  sugar,  C12H22011,  or  ®C«H1005  +  H2  0. 
Obtained  by  neutralizing  the  somewhat  acid  sap  of 
the  cane,  the  beet,  the  sorghum,  the  maple,  by 
means  of  chalk  (CaCO3),  and  by  evaporating  the 
clarified  liquid  rapidly — best  in  a  closed  boiling  pan 
from  which  vapors  and  air  are  steadily  withdrawn 
by  an  air-pump  (vacuum  pan).  From  the  thick 
syrup  fall  small  crystals ;  can  be  obtained  in  large, 
very  perfect  monoclinic  crystals  by  recrystallization, 
which  are  drained  from  mother  liquor  in  centri- 
fugal filters,  and  are  then  known  as  crude  sugar 
(90-95  per  cent.).  The  refineries  remove  the  5  or 
10  per  cent,  of  impurities.  Cane  sugar  is  easily 
soluble  in  cold  water,  2  parts  of  sugar  in  one  of 
water,  much  more  soluble  in  boiling  water,  slightly 
soluble  in  alcohol,  not  in  ether.  Melts  at  160° 
C.,  and  on  cooling  forms  a  vitreous,  glassy  body 
—candy.  Heated  at  200°  C.  it  becomes  black 


THE    HOMOLOGUES    OF    CELLULOSE.  343 

sugar  or  caramel  (black,  horny).  By  destructive 
distillation  it  forms  bodies  similar  to  those  from 
starch  or  cellulose.  Cane  sugar  forms  genuine  com- 
binations with  K20,  Na20,  CaO,  BaO,  SrO,  all  sol- 
uble in  water.  The  combination,  C^H^O11. BaO 
is  now  much  used  in  the  refining  process.  Concen- 
trated H2S04  acts  energetically  on  sugar,  SO2 ; 
H.CHO2  (formic  acid)  escape,  a  coaly  residue  re- 
mains. Boiling  HNO3  -f  IPO  converts  sugar  into 
oxalic  acid  (H2.C204),  water,  CO2  and  NO.  A  sugar 
solution  rotates  the  plane  of  polarization  to  the  right, 
like  dextrin.  If  a  solution  of  cane  sugar  be  kept 
digesting  on  the  water  bath  with  HC1,  or  H2S04  (a 
few  per  cent.),  its  right  rotation  diminishes  and 
turns  finally  into  left  rotation  ;  the  sugar  is  inverted. 
Glucose,  grape-sugar,  C6H1206  or  C6JI1005  + 
H20.  Is  largely  contained  in  honey  and  in  all 
fruits  and  berries.  Crystallizes  in  small  scaly  forms. 
Less  soluble  in  water  than  cane  sugar  (1  glucose — 
1J  cold  water).  More  soluble  in  alcohol  than  cane 
sugar.  The  crystals  contain  one  molecule  of  IPO. 
Melts  at  70°  C.  Does  not  taste  as  strongly  as  cane 
sugar.  Concentrated  H2S04  does  not  change  glu- 
cose into  a  coal-like  mass ;  the  glucose  combines 
with  the  acid  to  form  gluco-sulfw*ic  acid.  Glucose  is 
found  in  the  urine  of  persons  who  suffer  from  dia- 
betes. Copper  sulfate  +  glucose  -f  potassium  hydrate 
-f  water  gives  at  ordinary  temperature  red  or  yellow- 
red  cuprous  oxyd.  Cane  sugar  gives  such  a  result 
only  by  continued  boiling.  This  reaction  is  the 
best  to  distinguish  the  two  sugars  from  one  another. 


344  CHEMISTRY    SIMPLIFIED. 

Large  quantities  of  glucose  are  manufactured  from 
corn-starch  (in  U.  S.)  and  from  potato  starch, 
(Europe). 

CeH1  °05,  starch  +  water  +  H2S04  +" boiling 
heat  =  C6!!1 206,  glucose  +  H2S04. 

Mix  600  grs.  of  starch  with  700  c.c.  of  luke-warm 
water  into  a  milk.  Mix  100  c.c.  of  water  with  5  c.c. 
of  cone.  H2S04.  Heat  the  latter  to  boiling.  Let 
the  milk  flow  into  the  boiling  liquid,  but  not  so 
fast  as  to  interrupt  the  boiling  motion.  Keep  boil- 
ing for  3  hours,  replenishing  the  water  lost  by 
evaporation.  Perfect  solution  of  glucose.  Neutra- 
lize acid  with  chalk  while  boiling.  Filter  through 
bone  charcoal ;  evaporate  to  thick  syrup  and  let  cool. 
In  the  course  of  10  to  12  hours  the  syrup  will  change 
to  a  stiff  mass  of  small  crystals  of  grape-sugar. 
"Glucose  is  largely  used  as  a  substitute  for  malt  in 
the  brewing  of  beer,  also  as  an  addition  to  grape 
juice  before  fermentation  into  wine.  By  heating 
cellulose  with  dilute  H2S04  under  pressure  in  closed 
boilers,  it  changes  slowly  into  glucose  (saw-dust 
made  into  sugar). 

Fruit-sugar,  syrup,  levulose,  CGH1206.  Gives  the 
slimy  consistence  to  honey.  Contained  in  all  berries 
and  fruits  with  the  glucose.  Does  not  crystallize. 
Rotates  plane  of  polarization  to  the  left.  Invert 
sugar  (see  above)  contains  this  variety  of  the  family. 
It  combines  with  3  molecules  of  CaO  to  a  water-in- 
soluble body,  while  the  isomeric  cane  sugar  gives  a 
soluble  compound  with  CaO.  The  so-called  molasses 


THE    HOMOLOGUES    OF    CELLULOSE.  345 

or  melasse  in  French,  is  largely  composed  of  this 
sugar. 

Milk-sugar,  lactose,  Cl  2H2  2  Ol 1  +  H*  0.  Obtained 
in  hard,  colorless,  tetragonal  crystals,  by  evapo- 
rating the  liquid  obtained  by  straining  curdled 
milk.  Is  only  soluble  in  6J  parts  of  cold  water. 
Agreeable  sweet  taste,  but  not  as  str6ng  as  the  iso- 
meric  cane  sugar.  Does  not  melt,  but  loses  the 
water  of  crystallization  at  130°  C. 

Gum  arabic,  arabin,  C12#20010  +  H*  0.  Con- 
tained in  the  sap  of  many  plants.  It  flows  from  the 
bark  and  is  found  adhering  in  gum  drops  to  the 
bark  of  the  stem  or  the  twigs.  Specially  plentiful 
in  the  sap  of  the  acacia  trees.  Forms  with  little 
water  a  thickish,  sticky  solution.  Not  soluble  in 
alcohol.  Does  not  reduce  CuO  to  Cu20  as  does 
dextrin.  Furnishes  about  3  per  cent,  of  ashes. 


CHAPTER  XIX.' 

ALCOHOL,  SPIRITS  OF  WINE,  ETHYLHYDROXYD, 
C2H5(HO). 

THIS  important  substance  is  a  derivative  of  the 
sugars,  and  especially  of  glucose — grape-sugar.  The 
grape-juice  is  essentially  a  dilute  solution  of  glucose, 
has  a  pleasantly  sweet  taste.  When  this  solution 
remains  standing,  uncovered,  in  a  warm  place  (20° 
C.  to  30°  C.),  it  soon  becomes  turbid,  and  gas 
bubbles  arise  from  the  liquid  more  and  more  abund- 
antly until  the  liquid  begins  to  froth.  As  gradually 
as  this  action  has  increased  it  decreases,  leaving  a 
clear  liquid,  upon  which  rests  a  reddish  or  brown- 
ish scum,  while  a  similar  material  has  gone  to  the 
bottom.  The  liquid  has  now  assumed  a  sour  taste, 
but  very  agreeable,  and  when  taken  in  large  quan- 
tity produces  stupefaction  (drunkenness) ;  the  liquid 
is  then  known  by  the  name  of  wine  (Latin  =  vinum). 

Arab  experimenters  were  first  in  trying  to  get  at 
the  understanding  of  this  remarkable  action.  They 
succeeded,  by  distillation,  in  separating  the  active 
principle  of  wine  in  form  of  a  colorless  liquid,  very 
mobile,  and  of  agreeable  odor  but  burning  taste. 
They  found  that  this  liquid  will  burn  with  a  bright 
and  very  hot  flame.  The  name  al-Kohol,  the  breath 
spirit  (from  spirare,  to  breath)  was  given  to  this  re- 
(346) 


ALCOHOL,  SPIRITS  OF  WINE,  ETHYLHYDROXYD.    347 

markable  liquid.  The  Latin  translator  of  the 
Arabic  treatise  translated  al-Kohol  into  spiritus  vini, 
French,  esprit  de  vin ;  German,  weingeist  (the  spirit 
or  soul  of  the  wine).  However,  in  recent  years  the 
chemists  of  all  nations  use  the  word  alcohol  exclu- 
sively. 

The  process  described  above,  by  which  a  solution 
of  sugar  converts  itself  into  a  solution  of  alcohol,  is 
now  everywhere  known  as  fermentation,  the  Germans 
alone  use  an  indigenous  word  gaehrung.  But  simi- 
lar processes  are  known  to  yield  other  products  than 
alcohol ;  hence,  to  be  clearly  understood,  we  say 
alcoholic  fermentation.  The  chemical  process  of  this 
fermentation  is  of  the  simplest. 

C6H1206,  glucose  +  water+ferment  =  2C2H5(HO), 
alcohol  +  2C02. 

The  gas  bubbles  forming  in  the  process  are  CO2. 
The  ferment  or  yeast  is  found  in  the  matter,  which 
causes  the  turbidity  of  the  fermenting  liquid,  and 
which  either  rises  to  form  the  scum  or  sinks  to  form 
the  sediment.  This  matter  is  biological ;  it  is  alive. 
Under  sufficient  magnifying  power  the  scum  differ- 
entiates itself  into  cells,  single  or  in  clusters.  The 
cells  have  an  envelope  of  cellulose,  and  are  filled 
with  a  clear  liquid.  The  liquid  contains  protoplasm, 
which  can  be  separated  as  white  Hocculae.  The 
white  substance  dries  into  a  horny  body,  the  analysis 
of  which  gives  C  =  55  ;  H  =  7.5  ;  X  =  14  ;  0  +  S  = 
23.4.  In  this  body  rests  the  life-potency  of  the  cell. 
The  cells  multiply  by  "  budding,"  as  shown  in  Fig. 


348  CHEMISTRY    SIMPLIFIED. 

100.  A  yeast  cake  is  merely  a  multitude  of  such 
cells  with  some  potato  starch.  Botanists  classify 
these  yeast  cells  as  the  lowest  form  of  the  order 
fungi.  The  specific  name  is  saccharomycetes  cerevisise. 
Because  such  cells  are  in  the  air  with  other  minute 

FIG.  100. 

O 
CD 


dust,  the  fruit  juices  begin  to  ferment,  apparently 
by  themselves,  but  if  filter  paper  be  tied  over  the 
vessel,  no  fermentation  takes  place.  The  addition 
of  yeast  merely  accelerates  the  process. 

The  manufacture  of  ethyl-alcohol.  It  sometimes 
pays  to  distill  wine  (in  France),  but  only  in  excep- 
tional cases.  The  bulk  of  the  alcohol  is  made  from 
grain  or  potatoes.  The  process  is  essentially  identi- 
cal for  all  raw  materials.  It  comprises  the  follow- 
ing operations :  (1)  Grinding  of  the  grain  without 
sifting  off  the  bran.  (2)  Mashing  of  the  grain  with 
malt.  Under  the  word  malt  is  understood  sprouted 
barley  dried  after  sprouting,  and  ground.  The 
sprouting  of  the  barley  grain  develops  another 
mysterious  substance — diastase — which  possesses  the 
power  to  change  starch  into  glucose  more  rapidly 
than  sulfuric  acid.  Its  composition  is  not  known, 
not  supposed  to  be  a  living  thing  as  yeast.  10  parts 


ALCOHOL,  SPIRITS  OF  WINE,  ETHYLHYDROXYD.    349 

of  grain,  1  part  of  malt,  80  parts  of  water  heated  by 
steam  in  a  tub  to  75°  C.  until  the  conversion  of  the 
starch  is  completed  ;  that  is  mashing. 

(3)  To  cool  down  the  mash  to  18°  C.  and  transfer 
it  to  fermenting  vats  through  a  strainer.  (4)  Ad- 
dition of  sound  yeast  and  fermentation  of  the  wort 
(technical  name  of  the  strained  mash)  in  a  separate 
room  in  which  the  temperature  is  kept  evenly  at 
20°  to  25°  C.  The  end  of  the  fermentation  is  indi- 
cated by  the  collapse  of  the  froth  over  the  liquid. 

(5)  Distillation  of  the  alcoholic  liquor  in  copper 
stills.  Alcohol  boils  at  78°  C.,  water  at  100°  C. 
From  the  boiling  mixture  more  alcohol  passes  into 
vapor  than  water.  If  the  liquor  contains  5  per  cent, 
alcohol,  then  this  entire  quantity  will  have  gone 
over  when  28  per  cent,  of  the  liquid  has  distilled, 
leaving  72  per  cent,  of  liquid  in  the  still.  (This 
residue  is  not  thrown  away,  but  used  in  mixing  the 
feed  for  fattening  cattle.) '  The  distillate  contains 
now  20  per  cent,  alcohol ;  is  milky  from  minute 
drops  of  amyl-alcohol  (fusel-oil),  and  not  saleable. 
It  must  be  redistilled,  yielding  a  40  per  cent, 
brandy,  and  this  again  distilled  to  get  a  60  per  cent, 
spirit,  and  this  again  and  again  until  a  95  per  cent, 
proof  spirit  results.  Beyond  this  the  water  cannot 
be  eliminated  by  distillation  alone. 

By  mixing  with  fused  CaCl2,  or  calcined  copper 
vitriol,  CuSO4,  the  water  is  taken  up  by  these  bodies, 
and  another  distillation  yields  absolute  alcohol, 
C2H5(HO).  The  latter  is  only  needed  for  special 
chemical  purposes.  The  process  of  concentrating 


350  CHEMISTRY    SIMPLIFIED. 

the  alcohol  by  distillation  is  called  rectification.  To 
save  the  largest  part  of  the  fuel  required,  many  im- 
proved processes  have  been  invented,  which  at  last 
resulted  in  an  apparatus  yielding  proof  spirit  at  the 
first  operation.  This  is  done  by  carefully  cooling 
the  vapors  in  an  apparatus  of  large  cooling  surface, 
the  dephlegmator,  known  also  as  a  column  apparatus, 
which  stands  directly  above  the  still.  Fusel  oil  and 
other  complex  side-products  are  removed  from  the 
alcohol  in  the  dephlegmator. 

Properties  of  alcohol.  A  colorless,  mobile  liquid ; 
remains  liquid  even  at  — 90°  C.;  boils  at  78.4°  C. 
Specific  gravity  at  +4°  C.  =  0.8095,  at  +15°  C.  = 
0.795.  100  vols.  at  +4°  C.  give  109  vols.  at  78°. 
Expands  therefore  thrice  as  much  as  water.  Taste, 
burning.  Pure  alcohol  destroys  the  organisms,  is 
poisonous  ;  dilute  alcohol  causes  intoxication.  It 
is  a  solvent  for  many  substances  which  are  not  sol- 
uble in  water — its  chief  use  in  the  laboratory. 

Chemical  constitution.  Analysis  gives  simply  the 
atomic  ratio  C2H60.  But  we  write  instead  (C2H5) 
(HO)  because  alcohol  acts  towards  acids  like  the 
hydroxyds  of  metals.  In  this  last  form  alcohol  is 
meant  to  appear  as  the  hydroxyd  of  the  monovalent 
radical  (C2H5).  But  the  latter  may  be  looked  upon 
as  a  complex  radical  made  up  of  the  simpler  hydro- 
carbons CH3.CH2,  or  we  may  say  that  ethyl  alcohol 
is  equal  to  two  groups  of  methyl  in  which  one  H  is 
represented  by  the  monovalent  (HO) 

JCH3 

\  CH2.HO. 


ALCOHOL,  SPIRITS  OF  WINE,  ETHYLHYDROXYD.    351 

One  hydroxyd  can  take  up  one  hydrogen  of  an  acid, 
hence  when  we  act  upon  alcohol  with  cone.  H2S04, 
we  obtain  2(CH3.CH2.HO)  +  H2S04=(CH3.CH2)2. 
SO4  +  2H20  =  ethyl  sulfate  or  CH3.CH2.HO  + 
HC1  =  CH3.CH2.C1  +  H20  =  ethyl  chlorid.  Such 
bodies  were  formerly  named  ethers,  now  they  are 
named  esters,  i.  e.,  salts  in  .which  the  metal  is  re- 
placed by  a  compound  carbon  radical.  When 
alcohol  is  heated  in  air  or  oxygen,  its  elements 
become  oxydized,  it  burns,  producing  much  heat. 

CH3.CH2.HO  4-  60  =  2C02  +  3H2O. 
The  absolute  heat  effect,  A  =  2  X  12  X  8240  +  6  X 
34000  =  401760  heat-units,  or  one  gram  of  alcohol, 
by  burning,  will  raise  the  temperature  of  97.99 
grams  of  water  from  0°  C.  to  100°  C.,  if  no  heat  be 
lost  by  radiation  and  conduction. 


CHAPTER  XX. 

SOME  IMPORTANT  DERIVATIVES  OF  ALCOHOL. 

Ether,  sulfuric  ether,  ethyl  oxyd,  C*HIQ.0.     This 
very  important  substance  originates  thus : 

2C2H5(HO)  +  H2S04  -  (C2H5)2S04  +  2H20. 
(C2H5)2S04  +  H20  +  heat  -  C4H100  +  H2S04. 

Bring  into  a  boiling  flask  JOO  grams  concentrated 
H2S04,  20  grams  of  water  and  50  grams  of  absolute 
alcohol.  This  will  give  ethyl  sulfate.  Now  close 
the  neck  with  a  three-hole  stopper.  Pass  through  one 
hole  a  long-stemmed  funnel,  through  the  second 
hole  a  thermometer  down  into  the  liquid  ;  through 
the  third  hole  a  knee-shaped  gas  evolution  tube,  and 
connect  the  latter  by  means  of  a  proper  reducer  with 
a  condenser.  Heat  until  the  thermometer  shows 
140°  C.,  and  maintain  this  temperature  by  letting 
in  absolute  alcohol.  Ether  +  water  will  go  over 
steadily  and  collect  in  receiver.  Shake  the  dis- 
tillate with  Ca(HO)2  -f-  water,  milk  of  lime,  to  neu- 
tralize acid  particles.  Separate  the  upper  stratum 
of  the  two  liquids  with  syphon.  It  contains  some 
water.  By  redistillation  in  presence  of  CaO  (burnt 
lime)  the  ether  is  obtained  pure,  CaO  uniting  with 
the  water  and  binding  it. 

Ether  is  a  thin,  very  mobile,  colorless  liquid,  of 
(352) 


SOME  IMPORTANT  DERIVATIVES  OF  ALCOHOL.       353 

strong,  penetrating,  but  agreeable  odor.  Sp.  G.  = 
0.736.  Boils  at  35°  C.,  hence  very  volatile.  Mixes 
with  alcohol  in  all  proportions,  but  does  not  mix 
with  water.  10  parts  of  water  dissolve  1  part  of 
ether.  It  dissolves  many  bodies  which  are  neither 
soluble  in  alcohol  nor  in  water,  notably  fats.  It 
ignites  easily  and  burns  withjuminous  sooty  flame  ; 
be  careful  in  avoiding  open  flames  in  the  neighbor- 
hood of  evaporating  ether. 

It  is  evident  that  ether  stands  to  alcohol  in  the 
same  relation  as  potassium  or  sodium  oxyd  to 
potassium  or  sodium  hydroxyd, 

K 


K  /    °'   H  }    °'  C2H5  }    °'      H     /    °' 

After  once  being  separated  it  does  not  show  any 
tendency  to  reconvert  into  alcohol. 

Ether  produces  unconsciousness,  stupefaction, 
when  the  vapors  are  taken  into  the.  lungs ;  it  is  an 
anaesthetic. 

Chloroform,  CHOP,  can  be  considered  as  marsh 
gas  in  which  3H  have  been  replaced  by  3C1.  It 
results  when  4  parts  alcohol,  3  parts  water  and  1 
part  bleaching  lime  are  heated  in  a  flask  or  retort  to 
the  boiling  point.  With  the  water  is  found  in  the 
receiver  a  heavy,  oil-like  liquid — chloroform.  The 
reaction  may  go  thus  : 

C2H60  +  2Ca(C10)2.CaCl2=CH2Cl2  +  3CaCl2  + 

CaCO3  +  2N20. 
2CH2C12  +  Ca(C10)2CaCl2  =  2CHC13  +  CaCl2  + 

Ca(HO)2. 
23 


354  CHEMISTRY    SIMPLIFIED. 

Colorless,  thick  liquid.  Odor  pleasant,  taste  sweet. 
Insoluble  in  water.  Specific  gravity  =  1.48.  Boils 
at  61°  C.  Its  vapors  are  more  poisonous  than  ether; 
it  was  formerly  much  used  as  an  anaesthetic. 

lodoform,  CHP.  A  yellow  solid  in  scaly  crys- 
tals. Insoluble  in  water,  in  acids,  in  alkalies. 
Soluble  in  alcohol  and  ether.  Used  much  in  medi- 
cine as  an  antiseptic  for  burns  and  wounds.  It 
originates  similarly  to  chloroform.  From  a  mixture 
of  alcohol,  KOH  or  NaOH  and  iodine.  First  forms 
K(IO)  +  KI.  Then  KIO  acts  on  the  alcohol  just 
as  Ca(ClO)2  does.  Work  out  equation. 

Aldehyde,  C2H3HO.  A  thin,  mobile,  colorless 
liquid.  Boils  at  21°  C.  and  has  a  suffocating  odor. 
Specific  gravity  =  0.801.  Origin  :  C2H5HO  + 
MnO2  +  H2S04  +  Aq  =  C2H3HO  +  MnSO4  + 
2H20  -f-  Aq.  In  presence  of  air  it  changes  into 
acetic  acid,  C2H3HO  +  0  —  C2H302.H.  It  is  there- 
fore a  strongly  deoxydizing  body.  A  glass  plate  can 
be  made  into  a  silvered  mirror  by  pouring  upon  the 
well-cleansed  surface  a  liquid  composed  of  AgN03-f 
NH4HO  +  C2H3HO  +  water.  In  this  liquid  we 
have  Ag20.2NH4HO  +  NH4.N03  +  C2H3HO  + 
water.  Now  Ag20.2NH4HO  +  C2H3HO  =  Ag2  + 
NH4.C2H302  +  NH4HO  +  IPO. 

Chloral,  C2C13HO.  A  colorless,  thin  liquid. 
Has  a  penetrating  odor,  attacks  mucus  membrane. 
Soluble  in  water.  This  solution  does  not  give  a 
white  precipitate  of  AgCl  when  AgNO3  solution  is 
added.  We  explain  this  by  saying  that  chlorine  is 
intraradical,  inside  of  the  radical,  not  in  the  form  of 


SOME  IMPORTANT  DERIVATIVES  OF  ALCOHOL.       355 

chlorid.  Specific  gravity  1.502.  Boils  at  94°  C. 
Jt  is  prepared  by  passing  dry  chlorine  into  absolute 
alcohol  until  the  evolution  of  HC1  stops :  C2H5HO+ 
8C1  =  C2C13HO  +  5HC1.  When  chloral  is  taken 
in  small  doses  (dissolved  in  water),  it  causes  a 
peculiar  intoxication  and  indifference  to  pain.  For 
this  purpose  it  is  given  by  physicians,  but  it  can  be- 
come a  dangerous  habit  for  the  patient. 

Mercuric  fulminate,  Hg.C2fil202.  Discovered  by 
Howard,  A.  D.  1800.  Liebig  and  Gay-Lussac 
found  correct  composition.  Properties.  Minute, 
white,  needle-shaped  crystals.  Soft  to  the  touch. 
Sweetish  metallic  taste.  Little  soluble  in  cold, 
more  in  boiling,  water.  Specific  gravity  =  4.42. 
Very  poisonous.  In  the  dry  condition  it  explodes 
violently  by  friction,  by  a  blow,  or  by  concentrated 
H2S04. 

Hg.C2N202  +  blow  =  Hg  +  2CO  +  2N. 
By  experiment  1  gram  furnished  78  c.c.  of  gas  with 
a  heat  generation  of  403.5  cal.  or  enough  to  heat  the 
products  of  combustion  of  explosion  to  a  temperature 
of  4200°  C.  Although  gun-cotton  gives  more  gas 
per  unit,  yet  the  explosive  effect  of  the  fulminate  is 
much  greater.  This  effect  is  often  called  by  the 
French  expression  brisance.  We  say  :  Mercuric  ful- 
minate is  the  most  brisant  explosive.  Why  ?  Prob- 
ably because  of  its  instantaneous  break-up  into  gas. 

Preparation.  We  dissolve  5  grams  of  mercury  in 
60  grams  of  HNO3  specific  gravity  1.34  (45  c.c.) 
which  gives  usHg(N03)  +  HNO3  +  N203  +  NO  + 
water.  When  the  metal  is  dissolved  we  cool  the 


356  CHEMISTRY    SIMPLIFIED. 

liquid  to  70°  C.  We  bring  50  grams  of  90  per  cent, 
alcohol  into  a  strong,  well-tempered,  J-liter,  round 
flask  and  pour  the  first  liquid  slowly  into  the  alcohol 
while  rotating  the  flask.  A  colorless  mixture  re- 
sults. Should  no  reaction  develop  at  once  we  place 
the  flask  upon  a  water-bath  until  small  bubbles 
begin  to  show.  Then  we  set  the  flask  under  strongly 
drawing  hood  or  out  of  the  window.  Usually  a 
very  violent  reaction  sets  in  with  large  masses  of 
white  fumes  emerging  from  the  flask.  When  the 
reaction  is  over  a  white,  flour-like  precipitate  of  the 
fulminate  is  found  on  the  bottom  of  the  flask.  We 
cool  the  liquid  to  ordinary  temperature  and  more 
fulminate  precipitates.  Then  we  pour  off  the  super- 
natant liquid,  wash  the  crystals  with  cold  water  until 
the  acid  reaction  ceases,  collect  the  powder  on  a 
filter  and  dry  it  on  the  water-bath  or  better  yet,  in 
a  current  of  warm  air,  or  still  better  we  keep  it  wet. 
Manufacture  of  percussion  caps.  To  reduce  the 
brisance  and  to  obtain  a  more  penetrating  flame  jet, 
the  fulminate  is  mixed  with  30  per  cent,  of  niter  for 
mining  caps,  or  30  per  cent,  of  potassium  chlorate 
for  dynamite  igniters.  1.  The  materials  are  moist- 
ened with  30  per  cent,  water  and  mixed  with  wooden 
rubbers  upon  a  polished  slab  of  marble.  2.  The 
paste  is  pressed  through  hair  sieves  and  thus  be- 
comes granulated.  The  granules  are  very  carefully 
dried,  spread  upon  paper.  The  dry  granules  are 
sifted  through  hair  sieves  to  remove  the  dust  par- 
ticles. 3.  The  granules  are  filled  into  the  caps  by 
special  machines.  The  sheet  copper  is  0.26  mm. 


SOME  IMPORTANT  DERIVATIVES  OF  ALCOHOL.       357 

thick.  The  head  has  a  small  cavity  Fig.  A  (Fig. 
101).  Into  this  drop  granules  to  the  extent  of  15 
milligrams  Fig.  B ;  a  stamp  presses  a  thin  copper 
foil  over  the  charge  Fig.  C,  and  the  cap  is  ready. 
This  latter  is  the  most  dangerous  of  the  operations. 

FIG.  101. 


B 


Since  the  charges  are  small,  not  much  damage  can 
ensue.  Heavy  charges  are  fired  with  larger  caps 
containing  300,  500,  750  mgs.  of  fulminate  charge. 
Torpedo  caps  contain  as  much  as  1,500  mgs.  of  ful- 
minate. 

Silver  fulminate,  Ag2.C2N202,  has  similar  proper- 
ties. 


CHAPTER  XXI. 

SOME  ORGANIC  ACIDS. 

WE  find  these  acid  bodies  chiefly  in  the  flesh  of 
berries  or  fruit,  in  the  free  state  or  in  the  form  of 
salts — esters.  There  is  a  multitude  of  them  and  only 
the  most  important  ones  can  be  mentioned  here. 

Formic  acid,  ant  acid,  H.CHO2.  A  colorless,  mo- 
bile liquid  of  very  pungent  acid  odor.  Solid  at 
-1°  C.  Boils  at  100°  C.  Specific  gravity  =  1.235. 
Causes  a  blister  on  the  skin.  Found  in  pyroligneous 
acid  (wood  distillation).  Causes  the  stinging  sensa- 
tion produced  both  by  ants  and  nettles.  It  forms  in 
many  ways  by  the  oxydation  of  organic  bodies, 
especially  the  carbohydrates.  Most  interesting  is 
the  synthetic  formation  by  the  action  of  CO  gas 
upon  KOH  at  100°  C.  Thus  : 

KOH  +  CO  =  K.CHO2  (potassium  formate). 

Then  K.CHO2  +  H2S04  +  heat  =  KHSO4  + 

H.CHO2. 

And  also  CO2  +  2K  +  H20  =  K.CHO2  +  KOH. 
Formic  acid  precipitates  many  metals  from  the  solu- 
tion of  their  salts  in  metallic  form.  HgO+H.CHO2 
+  heat  =  Hg  +  H20  +  CO2. 

Acetic  acid,  H.C2H*0*  or  (CH8)COOH,  a  color- 
less, mobile  liquid  of  pleasant,  pungent  odor.     Solid 
(358) 


SOME   ORGANIC   ACIDS.  359 

at  -f  15°  C.  (glacial  acetic  acid),  boils  at  109°  C. 
Sp.  gr.  at  18°  C.=  1.063.  On  adding  water  the 
specific  gravity  increases  until  1.0748  is  reached 
(acid  =  78  per  cent.,  water  =  22  per  cent.),  then  the 
gravity  decreases  with  the  addition  of  water  until 
1.00  is  reached.  Hence  it  follows  that  one  specific 
gravity  may  mean  two  very  different  acids  ;  for  in- 
stance, 1.069  can  mean  an  ao4d  of  96  per  cent,  and 
an  acid  of  33  per  cent.  An  acid  of  54  per  cent,  has 
the  same  specific  gravity  as  acid  of  100  per  cent. 
Glacial  acetic  acid  destroys  the  skin  as  readily  as 
oil  of  vitriol.  The  vapor  of  the  acetic  acid  burns. 
Acetic  acid  dissolves  many  oils  which  are  insoluble 
in  water.  The  acetates  of  all  metals  are  easily  soluble 
in  water,  hence,  lead  is  usually  employed  in  the  form 
of  acetate. 

Acetic  acid  finds  not  only  much  use  as  vinegar, 
but  also  in  the  chemical  laboratories  and  in  the 
chemical  arts,  such  as  dyeing  and  printing.  It  is 
the  oldest  acid  known  to  man,  as  it  forms  naturally 
when  sugar  solutions  stand  in  a  warm  place  in  con- 
tact with  air.  This  change  does  not  take  place 
unless  a  peculiar  fungus  —  mycoderma  aceti  —  is 
present. 

C2H5.HO  alcohol  +  O2  +  ferment  +  water  = 
C2H302.H  acetic  acid  +  IPO. 

Pure  acetic  acid  for  laboratory  use  is  prepared  by 
distilling  two  molecules  of  crystallized  sodium  ace- 
tate with  one  molecule  of  concentrated  sulfuric  acid 
in  glass  retorts ;  in  iron  retorts  for  commercial  use. 


360  CHEMISTRY    SIMPLIFIED. 

The  latter  are  furnished  with  an  alembic  or  helmet 
made  of  tin. 

Na.C2H302  +  H2S04  +  heat  =  H.C2H302  + 
NaHSO4. 

The  sodium  acetate  is,  at  this  time,  obtained  exclu- 
sively from  pyroligneous  acid.  (See  distillation  of 
wood  or  cellulose.)  The  pyroligneous  acid  is  first 
made  into  Ca(C2H302)2,  evaporated  to  dryness,  and 
the  mass  gently  roasted  to  destroy  tar  oils.  There- 
upon distillation  with  HC1  yields  fairly  pure  acetic 
acid,  containing  water.  This  acid  is  neutralized 
with  Na2C03  and  the  Na.C2H302  is  allowed  to 
crystallize.  The  crystals  are  distilled  with  H2S04. 
Manufacture  of  vinegar.  Raw  materials  are  all 
kinds  of  alcoholic  liquids,  especially  wine,  cider, 
spoilt  beer,  and  fermented  worts  from  the  glucose 
industry,  a.  From  wine.  In  open  barrels,  into 
which  wine  and  vinegar  are  filled.  The  vinegar 
brings  with  it  the  ferment.  The  latter  grows  rapidly 
into  a  thick  skin  over  the  whole  surface.  Vinegar 
is  finished  in  8-14  days  according  to  temperature  of 
the  room,  or  the  outside  air.  b.  From  dilute  alcohol, 
by  the  rapid  process.  The  barrel  B,  Fig.  102,  is  open 
at  the  top.  At  F,  F'  are  perforated  wooden  discs, 
so-called  false  bottoms,  the  space  between  the  two 
discs  being  filled  with  clean  pine  shavings.  The 
latter  are  soaked  with  good  vinegar,  and  upon  the 
top  layer  is  sown  a  culture  of  pure  mycoderma 
cells  (all  other  germs  are  excluded).  The  alcoholic 
liquid  is  then  distributed  by  the  holes  in  F/  over 


SOME    ORGANIC    ACIDS. 


361 


the  surface  of  the  shavings,  while  plenty  of  warm  air 
enters  through  the  holes  1,  2,  3,  4-,  etc.  The  acidi- 
fied liquid  is  drawn  from  the  spigot  into  the  pail, 
and  returned  to  the  top  of  the  barrel  as  many  times 
as  may  be  needed  to  convert  the  whole  of  the  alcohol. 

FIG.  102. 


It  is  possible  to  make  the  resulting  vinegar  as  strong 
as  30  per  cent.,  in  which  form  it  is  known  as  spirit 
vinegar,  which  for  cooking  purposes  is  diluted  with 
10  parts  of  water. 

Oxalic  add,  H2.C20*.  At  ordinary  temperature 
a  white,  or  colorless  solid.  Forms  readily  large 
crystals,  monoclinic  with  2  molecules  of  water  of 
crystallization.  H2.C204  +  2H20.  The  crystals 
show  a  sharp,  sour  taste,  no  odor.  Soluble  in  10 
parts  of  cold  water,  in  three  parts  of  boiling  water. 
Soluble  in  2J  parts  of  cold  alcohol,  in  1.8  parts  of 
boiling  alcohol.  The  crystals  lose  their  water  of 
crystallization  at  60°  C.  At  97°  C.  the  crystals  melt, 
at  higher  heat  break  up  into  CO2  +  CO  and  H.CHO2 
(formic  acid).  In  a  current  of  air  the  anhydrous 


362  CHEMISTRY    SIMPLIFIED. 

acid  can  be  sublimed  at  150°  to  155°  C.    The  vapors 
attack  the  mucous  membrane  and  are  poisonous. 

Chemical  properties.  Oxalic  acid  is  not  a  good 
solvent  for  the  metallic  oxyds  and  metals,  because 
the  oxalates  are  either  quite  insoluble  or  but  little 
soluble  in  water.  The  most  insoluble  oxalate  is 
calcium  oxalate  Ca.C204  +  2H20,  (quadratic  crys- 
tals). This  salt  is  not  soluble  in  acetic  acid  but 
soluble  in  HC1.  Oxalic  acid  is  therefore  our  best 
agent  for  separating  calcium  from  a  solution.  Ox- 
alic acid  decomposes  quickly  in  presence  of  an  oxy- 
dizing  agent. 

H2.C204  +  0=H20 


It  precipitates  gold  and  platinum  from  their  chlo- 
rids. 

2AuCl3  +  3H2C204+  water  =  2Au  +  6HC1  +  6C02 

PtCl4  •+  2H2C204  +  water  =  Pt  +  4HC1  +  4C02 

H2C204  +  H2S04  +  heat  =  CO2  +  CO  + 

H2S04.H20 

(best  way  to  get  pure  CO  for  experiments,  the  CO2 
being  removed  by  means  of  NaHO). 

Occurrence  of  oxalic  acid.  It  is  found  in  the  saps 
of  many  plants,  as  KH.C204,  especially  in  the 
leaves  of  sour  clover  (oxalis),  and  in  rumex  ;  also  in 
rhubarb  (as  CaC204).  It  forms  the  calculi  in  the 
bladder  and  kidneys  of  man. 

Manufacture.  There  are  two  ways.  (1)  By  action 
of  nitric  acid  upon  the  carbohydrates  —  sugar,  starch, 
wood. 


SOME   ORGANIC   ACIDS.  363 

Ci2H220n)  sugar  +  12HN03  +  water  = 
6H2C204,  oxalic  acid  +  11H20  +  12NO. 
Theoretically  1  part  of  sugar  requires  2.21  parts  of 
HNO3  or  5  parts  of  50  per  cent.  acid.  Practice 
shows  that  6  parts  are  needed  to  effect  complete  oxy- 
dation.  Reaction  is  energetic  after  once  started. 
When  evolution  of  gas  has  gone  down,  put  flask  on 
flame  and  boil  until  volume  o'f  liquid  is  J  of  original. 
On  cooling,  the  acid  crystallizes.  (2)  By  action  of 
KOH  -f-  NaOH  upon  sawdust  or  similar  refuse 
wood.  The  action  is  probably  as  follows  : 

C6H1005,  cellulose  +  2KOH  +  2NaOH  +  heat  = 
Na2.C204  +  K2C03  +  2CH4  +  CO  +  H20.  +  4H. 

The  temperature  should  not  be  above  240°  C.  to 
obtain  the  best  result.  At  a  higher  temperature 
Na2C204  changes  to  Na2C03  +  CO.  When  all  the 
wood  is  changed,  let  cool.  Extract  with  little  cold 
water,  which  dissolves  only  K2C03.  Then  dissolve 
residue  in  boiling  water  and  stir  with  an  equivalent 
of  Ca(HO)2. 
Na2C204  +  water  +  Ca(HO)2  +  boil  =  Ca.C204  + 

2NaHO. 

Filter.  Filtrate  is  evaporated  for  next  batch. 
Residue  is  decomposed  by  dilute  H2S04  giving 
CaSO4  +  H2C204.  Separate  the  liquid  (hot)  from 
the  solid  CaS04.2H20  by  means  of  a  filter  press  or 
centrifugal.  Evaporate  filtrate  until  crystals  appear, 
then  let  cool,  and  the  bulk  of  the  oxalic  acid  will  fall 
out,  and  after  air-drying  can  be  packed  and  shipped. 
In  spite  of  the  many  operations,  this  second  method 


364  CHEMISTRY    SIMPLIFIED. 

gives  the  acid  at  considerably  less  cost  than  the  first 
method. 

Lactic  add,  milk  acid,  H*.(C*H*  0s).  A  colorless, 
thick  liquid.  Strong  sour  taste ;  no  odor  when 
pure.  Specific  gravity  =  1.25.  Soluble  in  water, 
alcohol,  ether.  When  the  water-solution  is  evapo- 
rated a  part  of  the  acid  escapes  with  the  vapor,  but 
most  of  it  remains  as  a  syrup.  At  130°  C.  it  loses 
one  H20  and  becomes  so-called  anhydrous  acid, 
Q6JJ10Q5  (isomeric  with  glucose,  starch). 

Lactic  acid  can  be  separated  from  other  acids  by 
the  insolubility  of  some  of  its  salts,  especially 
Sn.C3H403.  The  calcium  lactate  is  somewhat  sol- 
uble in  cold  and  more  soluble  in  hot  water.  Lactic 
acid  is  found  in  sour  milk  ;  in  the  gastric  juice  ;  in 
certain  fermented  vegetables,  such  as  cabbage  and 
turnips.  It  forms  easily  from  glucose  or  any  other 
sugar  in  presence  of  the  lactic  ferment.  The  latter  is 
obtained  from  rotten  cheese  or  rotten  meat. 

Tartaric  acid,  wine  acid,  H2.C4:H4:06.  As  solid, 
in  colorless,  monoclinic  crystals.  Easily  soluble  in 
water,  much  less  in  alcohol,  and  not  at  all  in  ether. 
The  water-solution  rotates  the  plane  of  polarization 
to  the  right.  Strong  sour  taste.  Melts  at  170°  C., 
forming  a  vitreous  body — meta-tartaric  acid — with- 
out decomposition.  If  we  add  tartaric  acid  to  .a 
solution  containing  a  ferric  or  aluminic  salt,  and 
then  an  excess  of  NH4HO,  there  will  be  no  precipi- 
tate, enabling  the  chemist  to  effect  certain  separa- 
tions, otherwise  difficult. 

Salt  of  seignette,  Na.KC*H*0«  +  SH20.  Large 
crystals  showing  orthorhombic  hemihedry. 


SOME    ORGANIC   ACIDS.  365 

Calcium  tartrate,  Ca.C*H*0«  +  8H20  forms  by 
adding  lime  water  to  a  tartrate  solution.  Insolu- 
ble in  water. 

Tartar  emetic,  K(SbO)C4H406  +  JJ?2  0  soluble  in 
14  parts  of  cold  water,  in  less  boiling  water.  Ob- 
tained by  boiling  a  solution  of  ordinary  tartar 
(K.H.C4H406)  with  Sb203,-the  teroxyd  of  anti- 
mony. Used  as  an  emetic ;  causes  death  in  larger 
portions. 

We  obtain  the  tartaric  acid  from  the  tartar  or 
argol  which  is  the  name  of  the  hard,  stony  deposit 
in  the  casks  in  which  the  grape  juice  has  been  fer- 
menting. The  Germans  call  it  weinstein,  winestone. 
The  crude  tartar  is  a  mixture  of  the  acid  potassium 
tartrate  KH.C4H406  with  coloring  material  and 
yeast  cells,  and  calcium  tartrate.  The  tartrates 
were  originally  dissolved  in  the  juice  but  had  to  fall 
outin  measure  as  the  percentage  of  alcohol  increased, 
they  being  insoluble  in  the  latter. 

We  boil  the  fine  powder  with  15  parts  of  water 
for  some  time,  add  bone-black  or  charcoal  which  ab- 
sorbs the  coloring  matter,  and  filter  boiling  hot. 
From  the  filtrate  precipitate  small  crystals  of 
KH.C4H406.  They  go  under  the  name  cream  of 
tartar.  We  redissolve  in  boiling  water,  add  one 
equivalent  of  Ca(HO)2  and  keep  boiling  until  we 
have  KOH  +  insoluble  Ca.C4H4O6.  We  separate 
by  H2S04  after  filtering,  getting  CaS04.2H20  + 
H2.C4H406,  and  proceed  the  same  as  for  oxalic  acid. 

The  crude  tartar  is  used  in  assaying  as  a  deoxy- 
dizing  agent  and  alkaline  flux,  for  on  heating  in  a 


366  CHEMISTRY    SIMPLIFIED. 

covered  crucible  to  redness  a  decomposition  takes 

place, 

2KH.C4H406  +  red  heat  =  K2C03  +  3G  +  4CO  + 

5H20. 

Both  C  and  CO  act  as  deoxydizers  upon  metallic 
oxyds ;  while  K2 CO3  can  take  up  sulfur  or  silica, 
or  both. 

Citric  acid,  H*.CQH507.  A  tribasic  acid.  Large 
colorless  crystals,  orthorhombic  combinations 
H3.C6H507  +  2H20.  Very  sour  taste.  Easily 
soluble  in  water  and  in  alcohol.  The  acid  acts  in 
iron  solutions  and  aluminum  solutions  the  same  as 
tartaric  acid.  It  is  used  for  a  number  of  medical 
preparations,  especially  seidlitz  powders,  magnesium 
citrate  and  others.  Contained  in  sour  lemons,  in 
gooseberries. 

Preparation.  .  The  juice  is  pressed  from  sour 
lemons,  strained  and  neutralized  with  Ca(HO)2. 
The  calcium  citrate  is  nearly  insoluble  in  water,  and 
is  decomposed  like  the  tartrate  and  oxalate  with 
H2S04. 

Malic  acid,  H2C4H*05.  Imperfect  crystals,  re- 
sembling cauliflower.  Deliquesces  in  the  air,  form- 
ing a  syrup.  Very  sour.  Soluble  in  alcohol. 
Occurs  in  many  fruits,  especially  in  sour  apples, 
plums,  gooseberries,  etc.  Calcium  malate  is  easily 
soluble,  and  forms  large  crystals.  This  enables  the 
separation  of  the  acid.  Insoluble  lead  malate  is,  as 
a  rule,  prepared  and  decomposed  with  IPS. 

Tannic  acid,  tannin,  C14H200IB.  An  amorphous 
powder;  color  pale-yellow  or  brownish  ;  somewhat 


SOME    ORGANIC    ACIDS.  367 

shining.  Taste  very  astringent.  Very  soluble  in 
water,  barely  soluble  in  ether,  very  slightly  in 
absolute  alcohol.  Its  water-solution  gives  with 
Fed8  or  with  FeSO4  a  blue-black  color  and  later  a 
blue-black  precipitate,  insoluble  in  water.  Its  solu- 
tion gives  a  flocculent  precipitate  with  a  solution 
of  gelatine.  If  a  piece  of  fresh  skin  or  hide  is 
placed  in  the  tannin  solution,  the  tannin  will  grad- 
ually leave  the  liquid  and  precipitate  itself  on  the 
skin.  The  tannin  is  easily  oxydizable,  and  there- 
fore reduces  CuO  to  Cu20  in  presence  of  NaHO,  or 
KHO,  and  gives  Ag  with  AgNO8,  same  as  glucose. 
Hence  chemists  place  the  tannin  among  the  gluco- 
sids.  Its  chief  use  in  medicine  is  as  an  astringent  in 
affections  of  the  mucous  membrane.  It  is  used  to 
make  our  ordinary  black  ink.  We  obtain  the 
tannin  from  the  so-called  Turkish  nut-galls.  The 
latter  form  on  the  leaves  and  twigs  of  certain  plants, 
especially  oak  and  acacia,  after  a  sting  has  punctured 
the  leaf.  The  sting  comes  from  wasps  mostly,  who 
deposit  their  eggs  in  the  outflowing  sap.  The  sap 
hardens  and  forms  the  nut-like  excrescence  or 
growth.  The  nut-galls  contain  as  much  as  65  per 
cent,  of  tannin. 

Preparation.  We  extract  the  ground  galls  with  a 
mixture  of  30  volumes  of  crude  ether  (0.74),  4  vol- 
umes of  water,  1  volume  of  alcohol  (90  per  cent.). 
The  extract  separates  into  a  lower  layer,  a  syrup 
(tannin  and  water)  forming  the  upper  layer  is  com- 
posed of  ether-alcohol  with  a  little  tannin  and  all 
other  bodies.  The  water-syrup  is  evaporated  and 
leaves  shining  amorphous  tannin. 


368  CHEMISTRY    SIMPLIFIED. 

Recipe  for  black  ink.  125  grams  of  ground  nut 
galls,  24  grams  of  copperas  (FeSO4  -f  7Aq.)  24 
grams  gum-arabic,  1  liter  of  water,  1  gram  of  creo- 
sote. Boil  the  materials  for  1  hour,  replacing  the 
evaporating  water.  Strain  through  a  hair  sieve  or 
through  muslin.  Let  settle  for  a  week,  then  put  up 
into  bottles. 

Tanning  bodies  similar,  yet  not  quite  identical  with 
tannin  are  contained  in  the  barks  of  many  trees, 
especially  the  oak,  the  hemlock,  the  willow.  In  the 
tanneries  the  hides  are  first  cleansed  from  the  hair 
and  adhering  parts  of  flesh,  together  with  the  upper- 
most layer  of  cells — the  cuticle — by  scraping.  The 
clean  skins  are  spread  in  water-tight  pits  so  that  a 
layer  of  ground  bark  is  between  two  skins,  as  many 
as  100  skins  in  1  pit.  Then  the  pit  is  filled  with 
water  and  allowed  to  stand  quietly  for  several  months, 
the  longer  the  better.  The  water  draws  the  tanning 
bodies  from  the  bark  and  the  skins  take  it  from  the 
water-solution.  By  cutting  off  a  bit  of  the  skin  one 
recognizes  from  the  cross  section,  whether  the  change 
has  taken  place  to  the  very  core.  Then  the  skin 
has  become  leather.  It  is  perfectly  proof  against 
putrefaction.  It  has  become  impenetrable  to  water 
and  yet  it  remains  pliable  when  dried.  A  similar 
change  takes  place  in  the  skin  in  presence  of  alum, 
ferric  sulfate,  and  chromium  sulfate.  So  that  we 
have  now  tan,  iron,  chrome,  alumina  leather.  The 
scarcity  of  bark  has  brought  into  use  these  substi- 
tutes. 

Gallic    acid,    H.C7H*05  +  H20    crystallizes    in 


SOME   ORGANIC    ACIDS.  369 

silky  needles  of  the  triclinic  system.  Colorless  or 
pale  yellow.  Soluble  in  3  parts  of  boiling  water, 
slightly  soluble  in  ether  or  alcohol.  Action  on  metallic 
solutions  in  presence  of  NaHO  or  KHO  or  NH4HO 
like  tannin,  somewhat  more  energetic.  Forms  well 
crystallized  metallic  salts.  It  is  found  ready  in 
sumac  and  other  plants.  Prepared  by  allowing  a 
solution  of  tannin  to  cover  itself  with  fungi  (mildew) 
in  presence  of  yeast. 

Pyrogallic  acid,  pyrogallol,  H.C*H*03.  A  fluffy 
mass  of  thin  scales  and  needles.  Soluble  in  2.2 
parts  of  water  at  15°  0.  Solution  colorless.  Fed3 
gives  a  blue  color  with  this  body  ;  free  N203  pro- 
duces a  brown  color.  All  oxydizing  agents  produce 
a  brown  color.  An  alkaline  solution  turns  brown 
at  once  in  air.  It  acts  more  energetically  upon 
metallic  solutions  than  the  preceding  ones.  This 
gives  its  high  value  as  a  developer  in  photography. 
Here  the  AgBr  on  the  plate  becomes  changed  by 
the  action  of  light  and  becomes  capable  of  decom- 
posing water  in  presence  of  pyrogallate.  2(AgBr) 
active  +  H20  +  Na.C6H503  =  Ag2  +  2HBr  -f 
Na.C6H504  (the  brown  body);  the  ordinary  AgBr 
is  not  changed. 

Preparation.     By  heating  gallic  acid  thus  : 
H.C7H505  +  H20  +  heat  =  H.C6H503  + 

CO2  +  H20, 

hence  name  pyrogallic  from  pyro  =  fire. 
24 


CHAPTER  XXII. 

THE  VEGETABLE  FATS  AND  ANIMAL  FATS. 

MANY  plants  develop  in  their  seeds  an  oily  sub- 
stance, in  the  place  of  starch,  for  the  nutrition  of 
the  embryo  plant ;  the  cotton,  flax,  hemp,  rape, 
sesame,  anise,  poppy,  mustard,  and  among  the  trees 
all  the  so-called  nut-bearing  kinds :  palm,  walnut, 
beach,  hickory,  olive,  plum,  peach,  almond  and 
many  others,  while  some  grow  oil-bearing  roots  such 
as  the  pea-nut.  After  removing  the  hard  shell  from 
the  nuts  the  soft  kernels  are  crushed  between  rolls 
of  iron  or  stone,  the  pulp  is  warmed  to  about  60°  C, 
put  into  strong  hair  cloth  and  pressed  by  mechani- 
cal or  hydraulic  devices.  The  oil  runs  off.  The 
remaining  cake  is  very  nutritious,  containing  still  a 
good  deal  of  oil.  It  is  often  fed  to  the  cattle,  or 
used  as  manure  after  the  oil  has  been  fully  extracted 
with  carbon  disulfid.  Immense  quantities  of  these 
oils  are  made  annually  in  Europe ;  in  the  United 
States  cotton-seed  oil  and  linseed  oil  (flax)  are  the 
only  ones.  Most  of  the  plant  oils  remain  thick 
liquids  at  ordinary  temperature,  some  become  pasty 
(palm-oil)  and  a  few  are  solids. 

All  fats  and  oils  repel  water,  and  are  practically 
insoluble   in   water.     They  dissolve  in   alcohol,  in 
ether  and  in  carbon  disulfid.     Their  specific  gravity 
(-370) 


THE  VEGETABLE  FATS  AND  ANIMAL  FATS.   371 

is  mostly  smaller  than  that  of  water.  Between  the 
fingers  they  produce  a  slippery  sensation,  hence 
they  lubricate,  i.  e.,  reduce  friction.  They  taste 
pleasantly  or  unpleasantly,  and  each  oil  has  a  differ- 
ent odor  or  flavor.  However,  taste  and  flavor  are 
produced  mostly  by  small  quantities  of  special  oils, 
— flavoring  oils — essential  oils.,  while  the  mass  of  the 
fat  varies  but  slightly  in  composition  and  quality, 
yet  often  considerably  in  the  relative  quantities  of 
its  constituents.  Hence  each  oil  has  a  specific  boil- 
ing-point, and  also  a  different  fluidity — viscosity — 
which  is  measured  by  the  quantity  of  the  oil  which 
will  run  through  a  nozzle  of  standard  diameter 
in  one  minute  at  standard  temperature. 

TJie  animal  organism  develops  fat  upon  and  be- 
tween the  muscles,  in  the  hollow  bones,  partly  as 
lubricant,  partly  as  a  non-conductor  of  heat,  partly 
as  a  food  store  (sick  persons  lose  their  fat  first,  be- 
cause the  body  lives  upon  it  when  the  digestive 
organs  are  out  of  gear).  The  nerve  substance,  brain 
substance  is  fat,  and  the  yoke  of  the  egg  is  a  yellow 
liquid  fat  upon  which  the  embryo  of  the  oviparous 
animals  feeds.  Viviparous  animals  have  no  eggs, 
because  the  embryo  cell  receives  its  nourishment 
from  the  mother's  blood  through  the  navel  chord. 

The  animal  fats  are  solid  at  ordinary  temperature 
or  at  any  rate  pasty.  The  fat  lies  in  form  of  glob- 
ules within  a  loose  tissue  of  large  cells.  In  heating 
the  fat  the  cells  break,  the  globules  unite  into  one 
mass  and  the  cell  substance  (fibrin,  chondrin),  coag- 
ulates and  comes  to  the  surface  as  brown  scum. 


372  CHEMISTRY    SIMPLIFIED. 

Otherwise  the  animal  fats  act  like  the  vegetable 
fats  or  oils. 

Chemical  action  of  fats.  The  fats  prove  themselves 
to  be  esters  or  salts,  in  which  fat  acids  of  the  marsh 
gas  series,  CnH2n02,  with  high  value  of  n,  are 
united  with  glycerin,  which  has  the  properties  of  a 
triatomic  alcohol. 

/A 
A  fat  is  G£ A  or  G.(A)3 

XA 

when  G  stands  for  glycerine  and  A  for  a  monatomic 
fat  acid  radical.  This  view  is  deduced  from  the 
action  of  metallic  hydroxyds  upon  the  fats.  (1) 
NaOH  +  Aq  +  fat  -f  boiling  heat  yields  after 
sufficient  boiling  a  thick  paste,  soap,  which  is  com- 
pletely soluble  in  much  water,  and  quite  soluble  in 
a  few  volumes  of  alcohol.  Upon  adding  HC1  or 
JPSO4  (dilute)  to  the  solution  in  water,  a  white 
flocculent  body  separates.  If  the  liquid  be  heated 
to  near  boiling  point,  the  white  substance  melts, 
rises  to  the  surface  and  forms  there  a  layer  of  oil. 
On  cooling  the  oil  becomes  solid  or  semi-solid,  and 
represents  the  fatty  acids.  The  liquid  contains 
NaCl  +  HC1  +  water  +  glycerin.  The  glycerin 
was  discovered  by  the  Swedish  chemist  Scheele 
about  130  years  ago.  Being  an  apothecary  he  had 
to  make  adhesive  plasters  by  boiling  olive  oil  or 
other  fats  with  lead  oxyd.  In  this  process  the  fat 
acid  combines  with  PbO  into  a  pasty,  sticky  body, 
which  is  quite  insoluble  in  water.  Spreading  the 
paste  upon  linen,  muslin  or  silk,  makes  the  plaster. 


THE  VEGETABLE  FATS  AND  ANIMAL  FATS.   373 

Now  Scheele  noticed  one  day  that  the  water,  with 
which  he  had  washed  the  plaster,  possessed  a  sweet- 
ish taste,  and  this  led  him  to  work  until  he  had 
separated  this  sweet  body  in  the  form  of  a  thick 
liquid,  by  evaporation  ;  and  because  of  the  sweet 
taste  he  named  it  glycerin  from  glucos  =  sweet. 
He  knew  it  was  not  sugar  because  it  would  not  give 
alcohol  with  yeast.  The  composition  and  chemical 
nature  was  established  long  afterwards  by  J.  Liebig 
and  others.  Accordingly,  we  know  at  present  that 
glycerin  has  a  composition  represented  by  the  sym- 
bol C3H803;  that  towards  acids  it  acts  like  a 
base — a  hydroxyd,  with  3  replaceable  hydrogen 
atoms,  and  hence  we  write:  C3H5(HO)3  with  the 
probable  constitution  CH2(HO).CH(HO).CH2(HO). 
Properties.  At  ordinary  temperature  a  syrup.  At 
a  very  low  temperature  an  orthorhombic  solid,  which 
only  melts  at  17°-20°  C.  Boils  at  290°  C.,  and 
distills  without  decomposition  ;  more  readily  in  a 
current  of  steam.  At  150°  C.  it  ignites  on  approach- 
ing a  flame  and  burns  with  a  pale  blue,  non-lumin- 
ous flame.  If  salts  are  present  the  glycerin  breaks 
up  during  the  distillation,  thus  C3H803  -f  heat  = 
C3H40  -f-  2H20.  The  product  is  avrolein,  a  very 
disagreeably  smelling  substance  (the  odor  arising 
from  a  glowing  wick).  Glycerine  mixes  with  water 
in  all  proportions,  is  soluble  in  alcohol.  Not  soluble 
in  ether  nor  in  chloroform.  Pure  glycerine  is  hygro- 
scopic, attracts  water  from  the  air,  hence  it  causes  a 
burning  sensation  on  the  m  ucous  membrane.  Diluted 
with  1  volume  of  water  it  is  pleasant  on  a  chapped 


374  CHEMISTRY    SIMPLIFIED. 

skin  because  it  does  not  become  dry,  keeps  the  new 
skin  from  chafing.  Chemical  reaction :  A  borax 
bead  moistened  with  glycerin  colors  flame  green  ; 
without  glycerin  colors  flame  orange-yellow. 

Preparation.  Boil  90  grains  of  olive  oil  with  50 
grams  of  lead  oxyd  and  50  grams  of  water  until  the 
oil  has  disappeared,  the  plaster  formed.  Then  add 
more  water,  boil  a  few  minutes,  let  cool  and  drain 
the  Water  through  a  filter.  Pass  H2S  through  the 
liquid  to  remove  any  dissolved  lead,  filter,  evaporate 
below  the  boiling-point,  and  at  last  heat  the  syrup 
at  100°  C.  to  constant  weight. 

Manufacture  of  glycerin  is  a  part  of  the  manufac- 
ture of  stearic,  oleic,  and  palmitic  acids.  These  re- 
actions constitute  the  base  of  the  process  : 

1.  Saponification  as  above  with  hydroxyds. 

2.  Stearate  +  H2S04  +  water  +  heat  =  stearic 
acid  -j-  glycerin  -f-  sulfate  -j-  water. 

3.  Stearin  -f  water  +  heat  +  pressure  =  stearic 
acid  -f-  glycerin  +  water. 

The  last  reaction  gives  the  best  results.  It  is 
carried  on  in  2  cylindrical  steel-plate  boilers.  As 
much  as  1000  Ibs.  of  fat  can  be  taken  at  one  opera- 
tion. The  boilers  stand  one  above  the  other  verti- 
cally, and  communicate  by  means  of  2  tubes  so  that 
the  materials  circulate  and  the  temperature  equal- 
izes.. The  temperature  is  200°  C.  and  the  pressure 
accordingly  15.3  atmospheres  or  about  230  Ibs.  per 
sq.  inch.  Time  of  action  10  hours.  The  molten 
fatty  acids  collect  above  the  watery  glycerin,  the  latter 
is  drawn  off  at  the  bottom,  evaporated  in  a  vacuum, 


THE  VEGETABLE  FATS  AND  ANIMAL  FATS.   375 

and  furnishes  at  once  a  commercial  glycerin.  It 
has  a  yellow  color  and  contains  quite  a  number  of 
other  organic  bodies  in  small  quantities.  Best  puri- 
fication by  means  of  crystallization  at  -f  2°C.  and 
separation  of  crystals  from  mother-liquor  by  means 
of  centrifugal  machine. 

Tri-nitro-glycerin,  C*H5(NO*)*,  an  oily  liquid  at 
ordinary  temperature,  but  capable  of  solidification 
below    the    freezing-point.       Insoluble    in    water. 
Easily  soluble  in  ether.     Very  explosive  by  friction 
or  blow.     Begins  to  vaporize  at  75°  C.     The  vapors 
when   taken  into  the  lungs  cause  headache,   sick 
stomach.     Tri-nitro-glycerin  influences  the  action  of 
the  heart,  and  is  used  by  physicians  in  cases  of  col- 
lapse.    It  has  become  the  most  important  explosive 
for  blasting  since  Nobel  conceived  the  idea  of  letting 
the  oily  nitro-glycerin  be  soaked  up  by  infusorial 
earth  (4  parts  of  the  oil,  1  part  of  the  earth).     In 
this   form    it  is  known    as   dynamite.     The    white 
blasting  powder  now  in  use  in  many  mines  con- 
tains:  Nitro-glycerin    45-55  per   cent.;   soda  niter 
25-30  per  cent.;   wood  pulp  15-20  per  cent.;   mag- 
nesia 2-3  per  cent.     Wood  pulp  takes  the  place  of 
infusorial  earth,  and  the  niter  burns  up  the  wood  in 
the  explosion.     Such  a  composition  is  not  as  effective 
as  dynamite,   but  on   the   other   hand    it   can    be 
handled  with  less  danger,  and  it  does  not  shatter 
the  rock  as  much  as  dynamite.     Nitro-glycerin  dis- 
solves  gun-cotton,    yielding   a  jelly-like     material 
known    as    blasting   gelatine.     The    latter    can    be 
changed  into  a  hard,  horny  material,  granulated, 


376  CHEMISTRY    SIMPLIFIED. 

and  then   forms,  with   the  addition  of  ammonium 
picrate,  the  so-called  smokeless  powder. 

Manufacture  of  nitro-glycerine.  Reaction  : 
C8H5(HO)3  +  3HN03  =  C3H5(N03)3  +  3H20, 
temperature  10°  C.  to  20°  C.  Operation:  Prepare 
a  mixture  of  30  parts  of  95  per  cent.  H2S04  with 
28  parts  of  fuming  HNO3  (Sp.  Gr.  1.48).  Cool  this 
mixture  to  10°  C.,  weigh  out  10  parts  of  glycerin, 
stir  together  with  0.3  parts  of  concentrated  H2S04. 
Pour  the  glycerin  sulfate  in  a  thin  stream,  or  drop  by 
drop,  into  the  acid  mixture  while  stirring  the  latter 
with  a  thermometer.  The  temperature  rises — 
should  it  rise  above  20°  C.,  stop  pouring  and  cool 
the  liquid,  then  finish  pouring.  The  result  is  an 
emulsion  or  milky  liquid  which  soon  begins  to 
separate  into  two  distinct  layers.  The  upper  layer 
is  tri-nitro-glycerin  ;  the  lower  layer  is  sulfuric  acid, 
which  retains  some  nitric  acid.  After  some  hours' 
standing  the  acid  part  is  discharged  from  the  mixing 
vessel,  and  the  nitro-glycerin  run  into  cold  water, 
washed  several  times,  and  finally  with  a  5  per  cent, 
solution  Na2C03  to  remove  last  traces  of  acid. 
There  must  be  no  brown  fumes  during  the  mixing. 
Their  appearance  means  danger.  The  sulfuric  acid 
serves  to  take  up  the  3H20  of  the  process,  so  that 
the  HNO3  retains  its  concentration.  It  can  be  used 
over  and  over  if  the  water  is  boiled  out  of  it. 

Tallow  (from  beef  or  mutton)  contains  three  dif- 
ferent fats:  1.  Stearin,  CZH5.(C18H*5 O2)3,  glyc- 
erin tri-stearate.  A  hard,  white  crystalline  solid  at 
ordinary  temperatures  ;  melts  at  55°  C.  then  returns 


THR  VEGETABLE  FATS  AND  ANIMAL  FATS.   377 

to  solid  condition,  but  at  71.6°  C.  is  permanently 
liquid. 

2.  Palmitin,  C*H5.(C1«H*102)*,  glycerin  palma- 
tate.     Scaly    crystals ;   white,    luster   of    mother   of 
pearl.     Melts  at  46°  C.,  then  solidifies,  and  becomes 
permanently  liquid  at  62.8°  C. 

3.  Olein=C*H5.3(Cl*H*302), glycerin tri-oleate. 
Pure  olein,  is  a  colorless  oil  without  either  taste  or 
smell.     In  contact  with  air  it  absorbs  oxygen  and 
turns  "  rancid"  by  separation  of  "free"  oleic  acid. 
Oleic  acid  belongs  to  the  series  CnH2u-202. 

Soap,  saponification.  Soap  results  from  the  change 
of  the  glycerin  esters  into  sodium  or  potassium 
esters,  by  the  action  of  NaOH  or  KOH  : 

C3H5.(C18H3502)3,  stearin  +  3NaOH  = 
3Na(C18H3502),  soap  +C3H5(HO)3  glycerin. 

890  parts  of  stearin  require  120  NaOH  ;  100  parts  of 
stearin  require  13.4  parts  NaHO  and  furnish  10.3 
parts  of  glycerin  ;  while  the  quantity  of  soap  de- 
pends upon  how  far  the  water  is  removed  by  the 
process  of  boiling  and  salting,  for  in  a  solution  of 
NaCl  soap  is  more  and  more  insoluble  as  the  per- 
centage of  NaCl  rises  in  the  liquid.  This  distin- 
guishes soft  from  hard  soap.  The  process  of  chang- 
ing fat  into  soap  is  named  saponification. 

Drying  oils.  The  oils  from  flax  seed,  poppy  seed 
and  some  other  plants,  differ  from  other  oils  in  so 
much  as  they  become  dry  in  a  day  or  two  when  spread 
over  wood  or  any  other  solid  material.  The  surface 
has  become  covered  with  an  elastic  film.  A  second 


378  CHEMISTRY    SIMPLIFIED. 

and  third  coating  increases  the  thickness  of  the  film. 
The  latter  shows  luster  and  is  known  as  varnish. 
•  Other  oils,  such  as  olive  oil,  nut  oil,  etc.,  do  not  dry," 
they  turn  rancid  and  continue  to  be  greasy  fora  long 
time.  Hence  linseed  oil  or  poppy  seed  oil  is  used 
as  the  liquid  medium  in  painting.  The  oil  is  mixed 
intimately  with  the  colored  solids  oxyds,  salts,  earths 
after  the  latter  have  been  ground  to  exceedingly  line 
grain.  The  chemical  reason  for  this  drying  lies  in 
the  fact  that  the  chief  part  of  drying  oils  is  made  up 
of  linolein  instead  of  olein.  Linolein  is  C3H5.- 
(C16H2702)3.  The  linoleic  acid  is  H(C16H2702) 
and  is  known  as  an  unsaturated  acid  belonging  to 
the  series  CnH2n~402.  The  acid  absorbs  oxygen 
rapidly  and  becomes  oxy linoleic  acid;  the  latter  being 
the  varnish. 

Turpentine,  spirits  of  turpentine,  resin,  balsam.  All 
coniferous  plants  exude  from  their  bark  an  oily 
liquid,  which  soon  becomes  sticky  and  ultimately 
a  transparent  solid.  The  pitch-pine  of  the  Southern 
States  and  the  Canadian  balsam  fir  produce  this 
material  more  abundantly.  By  means  of  cuts  in 
the  trees  the  liquid  is  collected  in  the  woods  (same 
as  maple  sap).  It  is  usually  a  thick  liquid  of  pale 
yellow  color  and  strong  pleasant  odor.  This  tur- 
pentine or  balsam  contains  an  oil  named  spirits  of 
turpentine  and  a  solid  known  as  resin  or  rosin. 
The  oil  is  obtained  by  distillation,  usually  in  a  cur- 
rent of  steam.  The  residue  contains  several  similar 
bodies  insoluble  in  water,  but  soluble  in  part  in 
absolute  alcohol,  and  partly  insoluble.  The  Canada 


THE  VEGETABLE  FATS  AND  ANIMAL  FATS.   379 

balsam  contains  oil  =  24  per  cent.;  resin  soluble 
in  absolute  alcohol  =  60  per  cent.;  insoluble  resin 
=  16  per  cent.  Spirits  of  turpentine,  a  clear,  color- 
less, mobile  liquid,  sharp  taste,  peculiar  pleasant 
odor.  High  refraction.  Insoluble  in  water,  little 
soluble  in  alcohol,  easily  soluble  in  ether,  chloro- 
form, carbon  disulfid.  Boiling-point  varies  between 
160°  to  180°  C.  Specific  gravity=0.85  to  0.89.  Ro- 
tates plane  of  polarization.  The  substance  may  be 
represented  as  a  hydrocarbon,  C10H16,  but  is  evi- 
dently a  mixture  of  several  hydrocarbons,  which 
have  not  been  separated  from  each  other.  Turpen- 
tine evaporates  very  rapidly  in  air  at  ordinary 
temperature  and  leaves  a  film.  Hence  it  is  known 
by  painters  as  a  quick  dryer  when  used  for  dilut- 
ing paint.  Its  chief  use  is  in  the  manufacture  of 
different  varnishes,  because  it  dissolves  the  resins. 

Rosin,  pine  rosin,  colophony.  Obtained  from  the 
heating  or  distilling  of  the  turpentine.  A  hard, 
brittle  substance,  of  yellow  to  brown  color,  sticks  to 
the  mortar  and  pestle  when  grinding.  Specific 
gravity  1.01  to  1.08.  Insoluble  in  water.  Softens 
when  heated,  then  melts.  Soluble  in  spirits  of  tur- 
pentine, in  absolute  alcohol,  in  ether,  etc.  Chem- 
ically this  substance  must  be  considered  as  an  acid 
— alcoholic  solution  reddens  litmus.  This  body 
has  been  named  abietinic  acid,  C44H6204  +H20. 
It  combines  with  the  metallic  hydroxyds  to  form 
soluble  and  insoluble  salts,  esters.  With  KOH 
or  NaOH  results  soluble  (water)  potassium  or 
sodium  abietinate;  with  Ca(HO)2,Pb(OH)2,  etc., 


380  CHEMISTRY    SIMPLIFIED. 

result  insoluble  bodies.  The  acid  is,  therefore, 
analogous  with  the  fatty  acids.  Rosin  is  frequently 
added  in  soap-making. 

Pitch  is  the  name  given  to  the  somewhat  elastic 
body  obtained  by  the  destructive  distillation  of  rosin, 
or  resinous  wood. 

There  are  a  great  many  other  rosin-like  substances 
from  other  plants,  each  with  peculiar  properties. 
They  are  all  used  in  making  varnishes. 

Rubber,  caoutchouc,  gutta-percha.  Obtained  by 
evaporation  of  the  milky  sap  of  certain  tropical 
trees,  and  of  immense  importance  to  modern  civili- 
zation. The  gutta-percha  tree  is  from  40-70  feet 
high.  The  leaves  are  inverted,  oval  and  leathery. 
By  means  of  incisions  at  different  heights  the  sap  is 
made  to  flow.  It  sets  or  coagulates  shortly  after 
leaving  the  tree  and  then  dries  out  into  a  tough, 
elastic,  light-colored,  leathery  substance  which  is 
impermeable  to  water,  therefore  even  the  natives 
knew  how  to  make  flasks  and  bottles  of  it.  Rubbing 
causes  negative  electrification.  Very  poor  conduc- 
tor. In  contact  with  air  it  absorbs  oxygen,  increases 
in  weight,  becomes  brittle.  Under  gentle  heat  the 
gutta-percha  becomes  soft  and  plastic,  whence  its 
great  serviceability.  Melts  at  120°  C.  into  a  thin 
liquid  ;  at  higher  heat  forms  vapors  of  a  disgreeable 
odor.  The  analysis  of  pure  gutta  gave  C,  86.36 ; 
H,  12.15  ;  O,  1.49.  The  great  mass  of  the  gutta  is 
probably  a  hydrocarbon,  the  oxygen  belonging  to  a 
secondary  body.  C6H10  is  probably  the  nearest  ap- 
proach to  the  formula.  The  gutta  is  somewhat 


THE  VEGETABLE  FATS  AND  ANIMAL  FATS.   381 

soluble  in  absolute  alcohol.  Easily  soluble  in 
chloroform  and  carbon  disulfid. 

Under  the  name  caoutchouc  (Indian)  goes  a  variety 
of  rubber  which  comes  from  the  milk-sap  of  a  num- 
ber of  trees  belonging  to  different  families  and  quite 
unlike  the  gutta  plant.  Some  of  the  trees  are  of 
enormous  size,  135  feet  high,  25  feet  diameter.  One 
tree  can  produce  as  much  as"  60  Ibs.  of  rubber  per 
year  without  suffering.  The  fresh  sap  has  an  acid 
reaction.  Contains  in  100  parts  caoutchouc  =  31.5  ; 
albumen  =  2.0  ;  a  bitter  substance  =  7.0  ;  insoluble 
in  water  and  alcohol  =  3.0  ;  water  =  56.5.  Hand- 
ling of  sap  :  The  sap  is  mostly  spread  upon  boards 
and  dried  upon  a  slow  fire  ;  the  resulting  film  is 
drawn  off,  and  many  films  are  kneaded  into  one  mass 
with  water.  By  another  method  the  sap  is  allowed 
to  stand  24  hours.  The  rubber  rises  to  the  top  and 
looks  like  cream,  (a  double  volume  of  water  having 
been  first  added).  The  water  is  let  out  at  the  bottom 
and  fresh  water  is  added  until  it  runs  off  clear.  A 
solution  of  alum  is  then  added  to  the  cream,  and  the 
the  caoutchouc  separates.  It  is  kneaded  to  remove 
the  liquids  and  then  dried,  but  often  retains  much 
w;ater  when  it  reaches  the  factory. 

Caoutchouc  contains  the  hydrocarbon  C6H10  in 
varying  proportion  depending  on  the  species  of 
plant,  upon  the  local  climate,  the  soil,  and  especi- 
ally the  treatment  of  the  sap.  Physical  properties : 
High  elasticity,  transparency  in  thin  sheets.  Indif- 
ference towards  acids  and  alkalies  except  the  con- 
centrated H2S04,  HNO3  at  elevated  temperature. 
Easy  adherence  of  two  fresh  surfaces  (making  of 


382  CHEMISTRY   SIMPLIFIED. 

tubes).  Impermeable  to  water,  but  permeable  to 
gases.  Pure  rubber  changes  on  exposure  to  light  and 
air  into  a  more  or  less  brittle  body.  Can  be  restored 
somewhat  by  exposure  to  the  vapors  of  alcohol. 

Vulcanizing  of  rubber.  The  fact  that  rubber  be- 
comes soft  and  smeary  at  a  relatively  low  heat  reduces 
its  usefulness.  This  defect  can  be  remedied  somewhat 
by  impregnating  it  with  sulfur.  In  molten  sulfur  the 
the  rubber  takes  up  as  much  as  15  per  cent.  S.  But 
it  also  absorbs  sulfur  if  the  latter  in  the  form  of  fine 
powder  is  kneaded  together  with  the  fine-cut  rubber 
and  then  rolled  out  into  sheets  or  blocks.  Thus 
prepared  the  material  is  less  permeable  to  gases  and 
does  not  get  smeary  when  warmed.  Ink  eraser  is 
made  by  adding  fine  quartz  sand  to  the  sulfur. 
Zinc  oxyd,  or  prepared  chalk  are  kneaded  into  the 
rubber  to  make  strong  tubes  and  steam-packing 
washers.  A  solution  of  sulfur  in  CS2  or  SCI2  in 
contact  with  fine-cut  rubber  gives  sulfur  to  the 
latter.  The  actual  vulcanization  consists  in  heating 
(baking)  the  impregnated  rubber  to  a  temperature 
of  from  146°  to  170°  C. 

Hard  rubber,  ebonite.  A  horn-like,  usually  black 
substance  in  which  one  does  not  recognize  any  of 
the  usual  properties  of  rubber.  Replaces  wood, 
glass,  leather,  horn,  ivory  for  many  articles,  notably 
combs.  Can  be  pressed  to  assume  almost  any  shape. 
Excellent  non-conductor  for  electricity.  6  parts  of 
rubber  are  kneeded  with  3  parts  of  sulfur,  1  part  of 
zinc  sulfid  or  other  material,  then  heated  for  several 
several  hours  to  140°  C.,  and  pressed  in  iron 
moulds. 


CHAPTER  XXIII. 

ORGANIC  ALKALOIDS. 

THESE  bodies  are  of  special  interest  as  strong  stim- 
ulants or  direct  and  fatal  poisons.  Combine  with 
.acids  to  form  easily  crystallizing  salts  nearly  all 
soluble  in  water.  Some  turn  red  litmus  to  blue. 
They  are  the  direct  products  of  certain  plants,  in 
which  they  are  found  as  salts  of  organic  acids. 

Theobromin,  C7H*N*02.  The  stimulating  sub- 
stance in  cocoa  and  hence  in  chocolate.  Is  very 
slightly  soluble  in  water,  its  reaction  is  neutral. 

Caffein,  C8H10N402.  The  stimulant  in  coffee 
and  in  tea.  The  tea-leaves  contain  as  much  as  4 
per  cent.;  the  coffee  bean  only  one  per  cent.  It  is 
not  a  strong  base  ;  the  salts  are  decomposed  by  water. 

Urea,  CH*N20.  Colorless,  orthorhombic  prisms. 
Specific  gravity  1.45.  Taste  cooling  like  niter. 
Easily  soluble  in  water.  Reaction  neutral.  Com- 
bines with  acids  to  salts,  which  are  mostly  little 
soluble  in  water,  especially  the  precipitates  produced 
by  AgNO3  and  Hg(N03)2.  Urea  is  the  principal 
substance  contained  in  urine. 

Morphin,  Cl  ^H1 9  AT03.  White  or  colorless  ;  little 
soluble  in  water,  but  easily  soluble  in  acids.  Is  a 
narcotic  or  sleep  producer  ;  overdose  is  fatal.  Con- 
tained in  opium,  and  opium  itself  is  the  result  from 
(383) 


384  CHEMISTRY    SIMPLIFIED. 

drying  the  sap  which  runs  from  unripe  seed  cap- 
sules of  the  poppy. 

Chinin  or  Qainin,  C20H24N202.  White  solid, 
slightly  soluble  in  water  with  blueing  of  litmus ; 
strong  base.  Easily  soluble  in  acids — chinin  sul- 
fate  forms  white,  fluffy  needles,  and  is  usually  taken 
as  a  remedy  for  malaria  or  other  fevers.  Chinin  is 
extracted  from  the  bark  of  a  shrub  growing  in  Peru. 

Strychnin,  C27H22N202.  Colorless  prisms,  nearly 
insoluble  in  water  and  only  slightly  in  alcohol  or 
ether.  Soluble  in  acids.  The  sulfate  is  used  in 
medicine  in  minute  doses.  50  milligrams  of  the 
sulfate  constitute  a  fatal  dose,  inasmuch  as  the 
strychnin  causes  terrible  convulsions  and  lock  jaw. 
It  is  developed  in  the  fruit  and  seeds  of  the  strychin 
plant. 

Brucin,  C2SH26N20*  +  8H20.  Colorless  tetra- 
gonal prisms.  Easily  soluble  in  alcohol  and  ether, 
slightly  soluble  in  water.  Reaction :  Brucin  -f- 
HNO8  gives  red  body,  which  turns  into  a  purple 
precipitate  on  adding  SnCl2.  Made  use  of  to  detect 
nitrates.  Brucin  is  found  with  strychnin  in  the 
beans  of  the  Strychnos  Ignatii.  Brucin  is  poisonous 
but  not  so  violently  as  strychnin. 

Atropin,  C17H2SNOS.  Needle-shaped  prisms, 
silky  luster.  Tastes  very  sharp  and  bitter.  Salts 
do  not  crystallize  readily.  Is  very  poisonous.  When 
applied  in  dilute  solution  to  the  cornea  of  the  eye  the 
pupil  becomes  enlarged,  so  that  the  iris  seems  to  dis- 
appear. It  is  extracted  from  the  cherry-like  fruit  of 
atropa  belladonna,  (belladonna  signifies  handsome 


ORGANIC    ALKALOIDS.  385 

lady — because  the  ladies  of  fashion  have  made  use 
of  the  extract  to  make  their  eyes  more  fascinating). 

Cocain,  C11HBINO*.  Colorless  prisms  soluble 
in  alcohol.  Is  extracted  from  the  coca  leaves.  Pro- 
duces local  stupefaction  of  the  nerves  and  is  there- 
fore used  to  relieve  pain. 

Nicotin,  C10H14N2.  A  colorless  oily  liquid,  usu- 
ally yellow  because  not  quite  pure.  Odor  pene- 
trating, disagreeable  ;  soluble  in  water,  in  alcohol. 
Changes  red  litmus  to  blue.  A  strong  base.  Boils 
at  250°  C.  Very  poisonous.  A  small  dose  acts  as 
a  narcotic.  Extracted  from  the  leaves  of  tobacco. 
Fine  Havana  tobacco  contains  only  about  2  per 
cent.  Coarse  common  tobacco  as  much  as  7  per 
cent.  A  poultice  of  tobacco  leaves  on  any  part  of 
the  body  can  cause  convulsions  and  even  death. 
The  smoking  tobacco  has  been  fermented,  most  of 
the  nicotin  is  therefore  destroyed  and  NH3  is  formed. 
25 


OF   THE 

UNIVERSITY 

Of 


CHAPTER  XXIV. 

ALBUMEN  AND  ALBUMENOIDS. 

The  animal  body  is  composed,  from  the  chemical 
standpoint,  of  fat,  muscles,  bone  and  derivatives  of 
the  muscles.  The  muscles  or  flesh,  as  well  as  the 
skin,  hair,  tendons,  are  composed  of  albumenoids ; 
the  bone  is  calcium  phosphate. 

Albumen,  C72JET112JV18S2022.  Is  obtained  by 
evaporating  the  white  of  eggs  at  a  temperature  not 
exceeding  50°  C.,  and  thus, 

C72H112N18S2022 

obtained  represents  a  yellowish  transparent  mass 
with  a  specific  gravity  of  1.314.  With  water  it 
swells  and  then  dissolves.  It  has  an  alkaline  reac 
tion  (due  to  the  presence  of  KOH  and  K  salts). 
If  the  water  solution  be  heated  it  begins  to  become 
turbid  at  60°  C.  At  75°  C.  large  flakes  separate; 
the  albumen  is  coagulated,  and  a  faint  odor  of  IPS 
noticed.  The  addition  of  HC1,  H2S04,  HNO3  causes 
the  coagulation  without  heating ;  the  addition  of 
KOH  or  NaOH  prevents  coagulation,  even  at  boil- 
ing heat. 

Basic  lead  acetate,  (HO)Pb.A2,  forms  a  precipi- 
tate with  albumen.     The  percentage  composition  of 
dry  albumen  is  :  C  =  53.4,  H  =  7.0,  N  =  15.6,  0  = 
22.4,  S  —  1.6.     The  blood  of  all  animals  contains  a 
(386) 


ALBUMEN  AND  ALBUMENOIDS.        387 

colorless  substance  which  acts  like  the  white  of 
eggs,  and  a  similar  body  is  contained  in  the  sap  of 
all  plants :  they  are  known  as  blood  albumen  and 
vegetable  albumen.  What  biologists  call  protoplasm 
is  chemically  not  clistinguished  from  albumen,  but 
protoplasm  has  life  and  albumen  has  not.  To 
find  the  conditions  under  which  ordinary  albumen 
will  change  into  protoplasm  will  be  equivalent  to 
finding  the  source  of  life  itself.  A  very  grand  prob- 
lem, and  one  which  I  think  possible  of  solution, 
though  not  probable.  * 

All  derivatives  and  homologues  of  albumen  we 
call  albumenoids. 

Haemoglobin,  C  =  53.8,  H  =  7.3,  N  =  16.1,  S  = 
0.5,  Fe  =  0.4,  0  =  21.9.  This  body  gives  the  red 
color  to  blood.  Under  the  microscope  a  drop  of 
blood  reveals  a  colorless  fluid  in  which  spheroid 
red  bodies  float  freely,  together  with  pale  bodies  of 
the  same  shape.  The  first  are  known  as  the  red 
blood  corpuscles,  the  second  as  the  white  corpuscles 
or  leucophytes.  Diameter  about  0.013  mm.  The 
bulk  of  the  red  corpuscles  is  water  and  haemoglobin. 
Note  the  iron  in  the  composition.  The  red  color  is 
due  to  this  iron.  Haemoglobin  absorbs  oxygen, 
nitric  oxyd,  carbon  monoxyd,  hydrogen  cyanid. 

'  The  reason  for  the  very  fatal  action  of  CO  and  HCN 
upon  man  is  probably  due  to  this  property  of  the 

i  haemoglobin. 

Haematin,   L*8H51Fe*N* O9.     This  is  a  genuine 

!|  chemical  unit.     Blue-black  of  color,   insoluble  in 
water,  alcohol,  ether.     Soluble  in  solutions  of  KOH 


388  CHEMISTRY    SIMPLIFIED. 

NaOH,  NH4HO.  Also  in  dil.  H2S04.  The  alka- 
line solution  is  olive  green  in  thin  column  and  red 
in  thick  column.  Obtained  from  haemoglobin. 

Fibrin,  C  =  52.6,  H  ==  7.0,  N  ==  17.4,  O  =  21.8, 
S  =  1.2.  Fibrin  is  held  in  solution  in  the  fresh  blood. 
When  blood  is  in  contact  with  air  for  a  short  time 
it  clots,  becomes  thick.  Beating  with  a  paddle  sepa- 
rates from  the  blood  a  red,  stringy,  fine  fibrous 
mass,  which  is  fibrin  mixed  with  haemoglobin. 
The  clear  liquid  is  named  the  serum  of  the  blood, 
and  contains  the  blood  albumen  and  many  other 
bodies  besides  the  mineral  salts.  The  muscles  are 
chiefly  modified  fibrin,  so  called  hyssin,  creatinin, 
sarkin,  xanthine,  all  albumenoids. 

Casein  (cheese  stuff),  C  =  53.6,  H  ==  7.1,  N  ==  15.7, 
0  —  22.6,  8  =  1.0.  This  body  is  found  in  the 
skimmed  milk  together  with  milk-sugar  and  salts. 
Casein  is  the  chief  nutriment  in  milk.  It  is  well 
known  that  milk  curdles  and  then  has  a  sour  re- 
action. The  curds  are  composed  of  casein  and 
water ;  the  water  can  be  removed  by  pressing  and 
drying.  Casein  turns  into  cheese  by  the  action  of 
ferments. 

Horn,  hair,  skin  are  all  closely  allied  to  albumen, 
although  their  chemical  action  is  quite  different,  for 
these  bodies  are  quite  insoluble  in  water  and  in  all 
agents  except  concentrated  alkalies,  which  dissolve 
them  and  evolve  NH3  as  other  albuminoids. 


ALBUMEN  AND  ALBUMENOIDS.        389 

hair  horn  finger-nail  wool 
C  =49.8  50.7  50.2  49.8 
H  =  6.4  6.7  6.8  7.0 

N        =17.1         17.3         16.9         17.7 
0  +  8  =  26.7         25.3         26.1         25.5 
Boiling  water  changes  the  skin  into  gelatine  or  glue. 
Silk  is  partly  soluble  in  boiling  water,  which  ex- 
tracts   sericin,    C15H25N508,    and    leaves    fibroin, 

C15H23N5()6 

Distillation  of  albumenoid  substances.  Animal 
charcoal.  When  albumenoid  bodies,  more  particu- 
larly the  hoofs  and  horns,  and  leather  scraps  of 
cattle  are  subjected  to  dry  distillation,  the  succes- 
sion of  phenomena  and  the  products  are  in  gen- 
eral similar  to  those  which  we  observed  in  the  dis- 
tillation of  wood  and  coal,  especially  the  latter. 
Yet  the  quality  and  quantity  of  the  products  are 
different. 

The  distillation  furnishes  (1)  a  black  residue — 
animal  charcoal ;  (2)  a  watery  ammoniacal  liquid, 
and  oils  (not  tar) ;  (3)  gases  of  exceedingly  strong 
and  disagreeable  odor.  Animal  charcoal  contains 
more  or  less  of  the  original  nitrogen  according  to 
the  degree  of  the  temperature.  Much  of  the 
nitrogen  goes  over  as  NH3.002  (carbamid)  and 
(NH4)2C03.  (This  used  to  be  the  chief  source  of 
ammonium  salts,  hence  the  expression  salts  of  and 
spirits  of  hartshorn). 

All  charcoal  has  the  faculty  of  attracting  coloring 
matter  which  may  be  either  actually  dissolved  or 
only  suspended  in  liquids  ;  but  animal  charcoal,  and 


390  CHEMISTRY    SIMPLIFIED. 

especially  bone  charcoal  (bone-black),  are  more  effi- 
cent  than  wood  charcoal.  The  oil  resulting  from 
this  work  is  known  as  the  oil  of  Dippel,  or  also 
neat's  foot  oil  much  in  use  formerly  as  a  lubricant 
for  clocks  and  watches  and  other  delicate  mechan- 
ism. It  does  not  turn  rancid,  nor  change  into  resin- 
ous sticky  substances  as  other  oils  do. 


CHAPTER  XXV. 
ORIGIN  OF  CYANIDS. 

WHEN  potash  (pearlash)  is  liquefied  in  an  iron 
crucible  or  pot  at  a  bright  red  heat  and  animal 
charcoal  (except  bone-black)  be  added,  the  charcoal 
disappears  amid  turbulent  evolution  of  gas.  (In 
practice  the  proportions  of  potash  and  charcoal  vary, 
perhaps  1  :  1  is  a  good  average.)  If  then  the  fused 
mass  be  digested  with  water,  or  boiled  with  the 
latter  in  the  kettle  or  iron  pot,  and  then  allowed  to 
stand  quietly,  there  will  be  found,  after  several  days, 
a  crop  of  yellow  quadratic  crystals  and  a  mother 
liquor  containing  K2C03,K2S,  and  some  other 
bodies.  This  liquor,  after  evaporating  to  dryness, 
can  be  used  in  the  next  operation  with  fresh  potash. 
The  crystals  are  of  exceeding  interest.  In  the  drug 
trade  they  are  known  as  yellow  prussiate  of  potash. 
The  German  chemist  Diesbach,  of  Berlin,  was  the 
first  who  discovered  that  this  salt  gives  with  certain 
salts  of  iron  a  beautiful  blue  precipitate — known  as 
prussian  blue — but  kept  his  knowledge  as  a  secret;  the 
Englishman  Woodward,  in  1724,  published  the  first 
account  of  its  preparation.  In  1752,  the  French- 
man Nacquer  obtained  the  pure  salt,  the  phlogisti- 
cated  alkali,  but  only  through  the  genius  and  labors 
of  Scheele  (1732),  of  Gay-Lussac  and  Porret  (1814), 
(391) 


392  CHEMISTRY    SIMPLIFIED. 

of  Gmelin  (1822),  and  lastly  of  Liebig,  came  to  light 
the  true  nature  of  this  remarkable  substance,  which 
chemists  now  call  unanimously  potassium  ferrocya- 
nate  and  give  to  it  the  symbol  K4(Fe(CN)6).  The 
symbol  assumes  the  existence  of  a  radical  (Fe(CN)6) 
of  the  valence  four.  Within  this  larger  radical 
there  are  six  units  of  the  smaller  radical  (CN)  = 
cyanogen.  The  larger  radical  is  ferro-cyanogen, 
which  some  chemists  write  FeCy  and  therefore  the 
yellow  crystals  are  K4FeCy  +  3H20.  One  ,sees 
here  the  very  positive  iron  become  a  part  of  a  very 
negative  complex  radical,  in  such  a  way  that  from 
a  solution  of  this  salt  the  alkaline  hydroxyds  do  not 
precipitate  any  iron  hydroxyd,  nor  does  H2S  precip- 
itate any  FeS  when  passed  into  the  alkaline  solu- 
tion. But  for  an  understanding  of  this  strange 
complex  it  will  be  necessary  to  break  down  the  com- 
plex form  in  order  to  get  at  the  fundamental  unit 
cyanogen. 

Properties  of  potassium  ferrocyanate.  Commonly 
the  crystals  show  a  light  lemon-yellow  color ;  color 
is  sometimes  orange.  The  crystals  are  very  cleav- 
able  parallel  to  the  basal  plane  and  the  cleavage 
plates  are  pliable,  elastic.  The  salt  dissolves  in  4 
parts  of  water  at  ordinary  temperature,  in  2  parts  at 
boiling  temperature.  It  loses  its  water  of  crystal- 
lization between  100°  and  110°  C.  and  becomes  an 
opaque,  chalk-like  mass.  At  red  heat  it  melts  and 
decomposes  with  evolution  of  nitrogen  gas,  thus : 

K4(Fe(CN)6)  +  red  heat  =  4K(CN)  +  2C  +  Fe+2N. 


OEIGIN    OF    CYANIDS.  393 

The  fused  mass  is  grey.  Water  extracts  a  colorless 
solution  of  K(CN),  potassium  cyanid,  leaving  behind 
a  black  mixture  of  iron  and  carbon  and  iron  carbid. 
Potassium  cyanid,  K(CN).  C  =  18.4,  N  =  21.5, 
K=60.1.  It  is  a  white  crystalline  body.  Easily 
soluble  in  water.  Insoluble  in  95  percent,  alcohol ; 
but  in  warm  50  per  cent,  alcohol  it  is  fairly  soluble. 
On  cooling  the  solution  will  deposit  isometric  cubes 
or  cubo-octohedrons  similar  to  KC1  or  NaCl.  The 
salt  itself  as  well  as  the  solutions  emit  the  strong  and 
peculiar  odor  of  bitter  almonds,  because  the  CO2  of 
air  decomposes  the  solution  (and  the  solid  salt  in 
moist  air  also)  thus  : 

2K(CN)  +  H20  +  CO2  =  K2C03  +  2H(CN). 

The  odor  is  due  to  H(GN)  =  hydrogen  cyanid.  The 
solution  of  K(CN)  in  water  does  not  bear  heating, 
and  therefore  cannot  be  concentrated  by  boiling  as 
other  salt  solutions,  because  the  salt  breaks  up  thus : 

K(CX)  +  2H20  +  water  +  heat  =  K(CHO2)  + 
NH3  +  water. 

That  is,  potassium  cyanid  breaks  up  into  potassium 
formate  and  ammonia.  This  behavior  should  be 
well  remembered. 

Preparation.  Pulverize  the  yellow  ferrocyanate 
coarsely.  Heat  in  a  flat,  iron  dish  or  pan  to  expel 
water  of  crystallization.  The  salt  turns  wrhite. 
Fill  it  into  an  iron  crucible,  which  stands  in  a 
furnace,  after  admixing  dry  pearlash  in  the  ratio 
of  3  parts  of  pearlash  to  8  parts  of  the  dehydrated 
ferrocyanate.  Cover  with  an  iron  lid  and  heat  grad- 


394  CHEMISTRY    SIMPLIFIED. 

ually  to  yellow   heat.      The   K2C03   is  added   in 
order  to  save  all  the  cyanid,  thus : 

2K4(Fe(CN)6)  +  2K2C03  +  yellow  heat  = 

10K(CN)  +  2K(CNO)  +  2C02  +  2Fe. 
K(CNO)  is  potassium  cyanate.  The  product  is  thus 
a  mixture  of  5  molecules  potassium  cyanid  with  1 
molecule  potassium  cyanate.  The  cyanate  is  not 
harmful  for  any  of  the  ordinary  uses  of  the  cyanid. 
In  order  to  obtain  pure  KCN,  the  pearlash  is  left 
out.  When  the  mass  in  the  crucible  fuses  quietly, 
introduce  a  warm  glass  rod,  and  this  rod,  upon 
cooling,  must  be  covered  with  a  pure  white  film  of 
the  salts.  Tap  the  crucible  several  times  on  the 
floor  to  cause  a  perfect  settling  of  the  iron  particles 
and  pour  out  into  ingot  moulds. 

Chemically  pure  KCN  can  only  be  obtained  by 
passing  H(CN)  into  a  solution  of  KOH  in  alcohol, 
the  liquid  being  kept  cool.  Then  K(CN)  separates 
in  small  crystals.  Collecting  these  upon  a  filter 
they  can  be  melted  into  solid  cakes  of  desired  shape 
and  size.  K(CN)  is  very  poisonous.  It  is  used  to 
extract  gold  from  the  ores,  because  Au  dissolves, 
forming  a  double  cyanid,  but  only  in  presence  of 
air  thus : 

2Au  +  4K(CN)  +  H20  +  0  =  2Au(CN).K(CN)  + 

2KOH. 

A  very  dilute  solution  such  as  0.2  per  cent.  KCN  is 
just  as  efficient  as  a  strong  solution.  Silver  dis- 
solves similarly  and  all  silver  salts  except  Ag2S  and 
even  the  latter  slowly  in  presence  of  air.  Hence  the 


ORIGIN   OF   CYANIDS.  395 

use  of  KCN  in  cleaning  silverware,  in  fixing  photo- 
graphic negatives.  K(CN)  is  used  as  a  solvent  in 
electroplating  with  silver,  with  gold,  and  other 
metals.  It  is  used  for  separating  nickel  from  cobalt. 
Hydrogen  cyanid,  prussic  acid,  H(CN),  is  at  ordi- 
nary temperature  a  colorless  liquid.  Strong  odor  of 
bitter  almonds  or  peach  kernels.  Boiling-point  at 
26.5°  C.,  hence  exceedingly  volatile.  One  drop  upon 
a  glass  slide  solidifies  from  the  sinking  of  the  tem- 
perature due  to  the  rapid  evaporation.  Point  of 
solidification  lies  at  —  15°  C.  Specific  gravity  = 
0.696.  H(CN)  barely  reddens  blue  litmus.  This 
substance  is  so  very  dangerous  that  it  should  only 
be  handled  by  very  expert  persons.  Mixes  with 
water  and  with  alcohol  in  all  proportions.  The 
water  solution  exposed  to  light  decomposes  into  a 
brown  solid  and  NH3,  hence  such  solution  should 
not  be  kept,  but  should  be  prepared  whenever 
needed.  The  vapor  of  H(CN)  burns  with  a  purple 
flame.  H(CN)  is  changed  by  concentrated  HC1  or 
H2S04  into  formic  acid  H(CH02)  and  ammonium 
salt  thus  : 

HCN  +  2H20  +  HC1  —  H(CH02)  +  NH4C1. 

(Some  water  must  be  present). 

That  (CN)  is  a  monad  and  combines  with  one  H 
can  be  shown  by  decomposing  one  volume  of  the 
vapor  or  gas  over  mercury  by  K,  when  J  vol.  of 
hydrogen  results.  The  water  solution  of  H(CN) 
dissolves  oxyds  and  hydroxids,  forming  metallic 
cyanids : 


396  CHEMISTRY    SIMPLIFIED. 

HgO  +  2H(CN)  =  Hg(CN)2  +  IPO, 

Mercuric  cyanid  which  is  soluble  in  water. 

Preparation  of  H(CN).  The  reaction  HC1 + 
K(CN)  is  not  available,  because  the  solution  of 
K(CN)  does  not  stand  heating.  (See  above.)  But 
the  yellow  prussiate  is  available  for  this  purpose, 
with  the  following  scheme  : 

2K4(Fe(CN)6)  +  3H2S04  ==  6H(CN)  +  3K2S04  + 
K2(Fe2(CN)6)  a  blue  substance. 

Recipe.  Bring  into  a  short-neck  flask  30  grams 
pulverized  yellow  prussiate  and  a  cooled  mixture  of 
21  grams  cone.  H2S04  with  42  c.c.  of  water.  Con- 
nect with  Liebig's  condenser  and  let  the  end  of  the 
condenser  tube  dip  just  under  the  distilled  water 
(25  c.c.)  in  the  receiver.  Then  distill. 

Cyanogen,  C2 N2 .  (Kuaneos  =  Cy.).  This  radical 
is  at  ordinary  temperature  a  colorless  gas  of  peculiar 
odor  and  very  poisonous.  The  gas  shows  a  sp.gr. 
of  1.806.  It  is  inflammable  and  burns  with  purple 
flame.  Under  a  pressure  of  3  atmospheres  it  be- 
comes a  mobile  liquid  which  turns  into  a  mass  of 
crystals  at  -35°  C.  It  is  soluble  in  water  and  in 
alcohol. 

Preparation.  We  heat  in  a  small  retort,  or  in  a 
glass  tube,  mercuric  cyanid  (see  above),  the  latter 
breaking  up  : 

Hg(CN) 2  +  heat  =  Hg  +  C2  N 2 . 
Composition.     We  collect  the  gas  over  mercury  ; 
add  somewhat  more  than  2  volumes  of  0  and  J  vol- 
ume (H2+0)  fulminating  gas,  and  explode.     We 


ORIGIN    OF    CYANIDS.  397 

introduce  KOH  to  absorb  CO2.  Next  we  introduce 
hydrogen,  2  volumes,  and  explode  after  reading  the 
volume.  From  the  contraction  we  find  the  rem- 
nant of  0  after  first  explosion  (J  contraction  and  f 
contraction  for  H  consumed),  and  subtracting  this 
from  the  remnant  of  N  -f  H  we  get  at  the  vol.  of  N, 
and  in  the  absorbed  vol.  of*C02  there  is  J  vol.  of  C. 
And  then  we  find  that  1  vol.  cyanogen  gives  1  vol. 
C  +  1  vol.  N,  hence  cyanogen  in  the  free  state  is 
(C2N2)  not  (ON).  It  follows  also  that  here  is  an 
exception  to  the  law  which  we  found  previously. 
Here"  one  volume  of  an  element  uniting  with  one 
volume  of  another  element  yields  two  volumes  of  the 
combination.  In  cyanogen  the  two  volumes  give 
only  one  volume  of  the  product.  This  is  verified 
by  the  volume  weight  of  the  gas,  for. 

1  volume  of  C  weighs  1.072  grs. 

1  volume  of  N  weighs  1.250  grs. 


1  volume  of  C2N2  weighs  2.322  grs., 

>vhile  the  experiment  gives  2.326  for  one  volume  of 
cyanogen.  Cyanogen  combines  with  chlorine  to 
form  (CN)Cl,  a  terribly  poisonous  gas.  It  also  com- 
bines with  bromine. 

Sulfocyanogen,  (CNS)2,  forms  colorless  crystals. 

Hydrogen  sulfocyanate,  H(CNS),  a  colorless  liquid 
of  pungent  odor  like  HC1  and  strong  acid  reaction. 

Potassium  sulfocyanate,  K(CNS).  Colorless  crys- 
tals :  easily  soluble  in  w^ater  and  in  alcohol.  The 
solution  of  this  salt  gives  with  ferric  salts  a  blood- 


398  CHEMISTRY    SIMPLIFIED. 

red  solution  in  presence  of  free  acid.  Very  delicate 
reaction. 

Preparation.  Fuse  together  KCN  +  S  in  a  cru- 
cible, dissolve  in  water  and  crystallize. 

Potassium  ferricyanate,  red  prussiate  of  potash, 
K^Fe^CN)1 2).  A  beautiful  salt.  The  crystals  are 
of  deep  garnet-red  color  and  dissolve  very  easily, 
with  an  intense  yellow  color,  in  water.  The  crystals 
contain  no  water  of  crystallization. 

It  is  prepared   by   acting   upon   the  solution  of 
potassium  ferrocyanate  with  chlorine  ;  thus  : 
2K4(Fe(CN)6)  +  water  +  2C1  =  K^Fe^CN)1 2)  + 

2KC1  +  water. 

We  say  that  2  molecules  of  tetravalent  ferrocya- 
nogen  have  become  polymerized — have  coalesced — 
in  one  hexavalent  radical,  ferricyanoge7i,(Fe*(CNy^). 

In  qualitative  analysis  potass,  ferricyanate  serves 

to  reveal  the  presence  of  a  ferrous  salt  inasmuch  as 

they  combine  to  an  intensely  blue  compound,  thus : 

K6(Fe2(CN)12j  +  3FeS04  +  free  acid  +  water  = 

Fe^Fe^CN)1 2)  +  3K2S04  +  free  acid. 

Fe3(Fe2(CN)12)  is  known  as  a  blue  coloring 
material  under  the  name  of  TurnbuWs  blue. 

Potassium  ferrocyanate  gives  with  ferric  salts  a 
similar  combination  of  equal  intense  blue  color 
which  is  named  prussian  blue.  The  following  equa- 
tion represents  this  relation  : 

3K4(Fe(CN)6)  +  4FeCl3  +  free  acid  +  water  = 

Fe4(Fe(CN)6)8,  prussian  blue  +  12KC1  + 

free  acid  -|-  water. 


ORIGIN   OF   CYANIDS.  399 

Of  prussian  blue  as  well  as  of  TurnbulPs  blue 
there  is  a  water-soluble  variet}7,  which  results  when- 
ever an  excess  of  the  potassium  ferro-  or  potassium 
ferricyanate  is  added  to  a  ferric  or  ferrous  salt. 
This  soluble  form  is  known  as  wash  blue  in  the 
laundry  business. 

Potassium  cyanate,  K(CNO).  This  salt  results 
when  K(CN)  is  kept- liquid  in  presence  of  air. 

K(CN)  +  0  =  K(CNO)  at  red  heat. 

This  strong  affinity  for  oxygen  is  the  reason  why 
K(CN)  is  a  most  excellent  agent  for  deoxydation  at 
high  heat.  It  is  much  used  in  assaying  and  in 
blowpipe  work  thus : 

SnO2  +  2K(CX)  +  red  heat  =  Sn  +  2K(CNO). 

CuO  +  K(CX)  +  red  heat  =  Cu  +  K(CNO). 
The  aqueous  solution  of  potassium  cyanate  breaks 
up  even  at  ordinary  temperature ;  when  heated  to 
boiling  NH3  +  CO2  escape  and  K2C03  remains  in 
the  liquid. 
2K(CNO)  +  3H20  +  heat  -  K2CO3-f  C02-f  2NH3. 

Hydrogen  cyanate  can  be  made,  but  is  exceedingly 
unstable.  It  has  an  odor  somewhat  like  a  mixture 
of  SO2  +  HC2H302.  It  is  very  curious  that  if  a 
solution  of  (NH*)(CXO),  ammonium  cyanate  is 
evaporated,  only  water  escapes,  but  the  residue  has 
all  the  properties  of  urea,  (CH*N*0),  the  principle 
secretion  in  the  animal  and  human  urine. 

Cyanuric  acid,  H  3(C  3N 3  O3)  can  be  made  in  large 
colorless  crystals.  One  recognizes  that  this  is  the 
formula  of  cyanic  acid  multiplied  by  3.  It  results 


400  CHEMISTRY    SIMPLIFIED. 

from  the  heating  of  dry  urea  above  the  boiling-point, 
when  NH3  escapes  and  cyanuric  acid  is  left. 

Fulminic  acid  is  not  known  in  the  free  state.  But 
we  saw  above  that  the  analysis  of  the  mercuric 
fulminate  gives  HgC2N202.  Now  this  radical 
(C2N202)  is  just  the  double  of  the  radical  in  (CNO) 
cyanic  acid.  Hence  we  have  here  an  intensely 
interesting  polymerism  or  equal  percentage-com- 
position for  three  totally  different  substances. 


CHAPTER  XXVI. 
BONE-ASH  AND  PHOSPHORUS. 

THE  animal  skeleton  is  composed  of  bones.  The 
bone  again  can  be  separated  into  a  mineral  part 
(not  combustible),  into  gelatine  (glue)  and  into  fat. 
The  fat  may  be  extracted  by  any  of  its  solvents 
(carbon  disulfid,  ether,  chloroform,  etc.)  The  gela- 
tine can  be  boiled  out  by  water.  If  the  bone  after 
extraction  is  merely  dried  and  bleached  it  becomes 
fit  for  conversion  into  useful  and  ornamental  ob- 
jects (by  the  lathe  and  by  the  carving  tool).  If  it 
be  thrown  into  a  hot  furnace  it  will  be  converted 
into  bone-ash.  With  the  latter  and  its  chemical 
nature,  we  shall  now  occupy  ourselves. 

Bone-ash  is  infusible  and  somewhat  luminous 
at  a  high  temperature.  It  dissolves  in  HC1,  in 
HNO3  -|-  aq.,  but  not  in  H2S04.  There  is  usually 
a  disengagement  of  CO2  unless  the  burning  of  the 
bones  had  been  done  at  very  high  heat.  In  the 
latter  instance  a  small  quantity  of  the  ash  will  pro- 
duce a  brown  spot  (alkaline  reaction)  when  placed 
upon  a  strip  of  yellow  turmeric  paper.  It  acts  thus 
like  CaO.  The  solution  in  HC1  gives  a  white,  gel- 
atinous precipitate  when  NH4(HO)  is  added;  there- 
fore there  must  be  an  add  present  of  as  yet  unknown 
properties,  because  the  solution  of  calcite  in  HC1 
26  ( 401 ) 


402  CHEMISTRY    SIMPLIFIED. 

or  of  CaSO4  in  HG1  does  not  precipitate  with 
(NH4)HO.  The  presence  of  calcium  is,  however, 
made  certain  by  the  form  of  the  minute  crystals 
which  are  separated  upon  adding  cone.  H2S04  to 
the  HC1  solution  of  the  bone-ash.  These  crystals 
are  identical  in  shape  with  the  calcium  sulfate  or 
vitriol. 

But  since  we  have  learned  that  oxalic  acid  forms 
with  calcium  an  oxalate  which  is  not  soluble  in 
water  and  not  soluble  in  dilute  acetic  acid,  we  can 
apply  that  knowledge  right  here  to  advantage.  For 
we  find  the  precipitate  which  is  thrown  down  by 
NH4HO  in  an  HC1  solution  of  the  bone-ash  to  be 
quite  soluble  in  acetic  acid.  Adding  a  solution  of 
ammonium  oxalate  to  the  latter  a  bulky  white  pre- 
cipitate falls  and  thus  calcium  in  large  quantities  is 
proved  beyond  any  doubt.  Let  us  designate  the 
unknown  acid  as  Ax  ;  then  we  can  write  a  prelimi- 
nary scheme  for  what  we  have  thus  far  accomplished. 

Bone-ash  =  CaAx ;  solution  of  bone-ash  in 
(m  +  2)HC1  =  CaCl2  +  H2AX  -f  mHCl ;  the  pre- 
cipitate by  NH4HO  must  be  CaA\ 

The  acetic  solution  will  be  again 

H2  Ax  +  mNH4Cl  -f  nNH4(C2H302)  -f 
qH.C2H302  +  Ca(C2H302)2  -f- H20 -solution. 

To  this  solution  we  add  ammonium  oxalate 
(NH4)2C204,  and  thus  we  get  a  precipitate  and  a 
liquid.  The  precipitate  will  be  Ca(C204),  the  liquid 
will  contain  H2AX -f  NH4C1 -f  NH4(C2H302) + 
H.C2H302  +  (NH4)2C204  water.  We  filter  and 


BONE-ASH    AND    PHOSPHORUS.  403 

evaporate  to  dry  ness.  Then  we  heat  carefully  over 
an  open  flame,  causing  the  volatilization  of  NH4C1 
and  of  NH4(C2H302);  further  mcrease  of  heat  will 
eliminate  the  excess  of  (NH4)2O  and  we  will  have, 
probably,  H2AX,  the  unknown  acid,  or  perhaps 
(NH4)2AX ;  provided  that  this  unknown  acid  does  not 
easily  volatilize.  We  find  fhat  a  remnant  is  left ; 
that  this  remnant  imparts  a  green  color  to  the  flame, 
and  that  it  dissolves  in  water,  giving  a  colorless 
solution  which  shows  a  strong  acid  reaction.  We 
also  find  that  the  remnant  does  volatilize  at  a  red 
heat.  Thus  we  have  established  that  this  body  is 
probably  an  acid-forming,  non-metallic,  oxyd.  It 
is  not  probable  that  any  of  the  non-metallic  elements 
of  our  acquaintance  could  produce  such  a  residue, 
since  their  oxyds  are  very  easily  volatilized,  or  since 
they  form  hydrogen  compounds  which  are  quite 
volatile.  In  order  to  separate  the  element  a  treat- 
ment with  strong  deoxydizing  bodies  is  indicated,  to 
wit,  potassium,  sodium,  hydrogen,  carbon,  marsh  gas. 
Of  these  possible  agents  carbon  is  the  only  available. 
(Reasons  below.)  We  make  H2AX  into  a  thick 
syrup  by  using  H2S04  to  precipitate  the  calcium 
instead  of  using  NH4HO  and  (NH4)2O,  and  then 
evaporating.  Mix  charcoal  powder  with  it  until  a 
sticky  mass  results.  Heat  over  open  flame  until 
quite  dry,  and  then  fill  the  black  mass  into  a  tube,  F, 
Fig.  103,  of  hard  infusible  glass,  which  has  been 
closed  at  one  end.  By  placing  the  tube  upon  a 
brick  (1)  against  a  second  brick  (2)  and  using  a 
Bunsen  blowpipe  on  the  closed  end,  we  can  bring 


404 


CHEMISTRY    SIMPLIFIED. 


the  tube  to  the  required  temperature.  As  the  heat 
rises  we  begin  to  observe  a  peculiar  odor  at  the 
mouth  of  the  tube,  and  on  approaching  a  taper  a 
greenish  flame  develops,  a  white  smoke  rising  into 
the  air.  At  the  same  time  wax -like  drops  con- 
dense in  the  forward  part  of  the  tube  at  (3).  At 
length  the  flame  burns  more. and  more  with  a  pure 

FIG.  103. 


blue  color  (CO)  and  the  action  is  complete.  When 
the  tube  has  become  cold  we  cut  off  the  forward 
part  with  a  file  stroke  and  a  red-hot  rod  (glass  or 
iron).  The  new  substance  is  transparent  or  trans- 
lucent. Its  color  varies  from  pale  yellow  to  bright 
red.  (Probably  2  different  substances  ?)  It  is  soft 
as  wax.  It  emits  a  peculiar  odor  similar  to  that 
of  ozone.  A  white  fume  arises  from  it  steadily.  It 
melts  at  45°  C.,  and  begins  at  once  to  burn  with  a 
bright  flame  and  evolution  of  white  fumes.  Under 
water  it  can  be  melted  without  danger  of  ignition. 
It  dissolves  somewhat  in  alcohol,  more  in  fat  oils. 
If  such  solution  is  rubbed  over  the  hands  or  the  face 
those  parts  will  shine  in  a  dark  room  with  a  pale 
green  light.  This  property  has  been  the  justifica- 
tion for  giving  to  this  remarkable  elementary  body 


BONE- ASH    AND    PHOSPHORUS.  405 

the  name  phosphorus  (phos  =  light ;  phorus  =  car- 
rier). It  would  be  more  consistent  to  change  the 
name  tophosgen,  and  thus  obtain  a  consonant  series : 
Oxygen,  hydrogen,  nitrogen,  chlorogen,  brornogen, 
iodogen,  fluogen,  phosgen,  and  so  forth. 

(1).  Note.  Brand  was  the  first  to  obtain  phos- 
phorus, in  1674,  by  distilling,  in  a  clay  retort, 
the  residual  mass  from  evaporated  urine ;  but  that 
bones  contain  much  more  phosphorus  than  does 
urine,  was  only  discovered  100  years  later  by 
Scheele. 

(2)  Note.  Experience  has  shown  that  a  higher 
percentage  of  phosphorus  can  be  obtained  from  bone- 
ash  if  only  two-thirds  of  the  calcium  are  removed  by 
means  of  H2S04,  leaving  soluble  calcium  phosphate 
to  be  separated  by  filtration,  to  be  evaporated,  mixed 
with  coal  and  dried  before  distillation.  This  plan 
is  followed  in  the  match  factories. 

There  are  three  modifications  of  phosphorus. 

(1).  Common,  pale-colored,  phosphorus  which  crys- 
tallizes in  octahedrons  has  essentially  the  properties 
already  given.  Specific  gravity  =  1.83  at  10°  C. 
Above  45°  C.,  that  is,  in  the  liquid  state,  the  specific 
gravity  decreases  considerably  ;  with  the  temperature 
at  100°  C.  it  is  1.695;  at  200°  C.  =  1 .603.  At  the  boil- 
ing-point =  1.485.  Phosphorus  boils  at  250°  C.  and 
distills  over  in  an  atmosphere  of  hydrogen.  Kapid 
cooling  of  the  vapor  throws  the  phosphorus  out  in  a 
fluffy,  snow-white  condition  (flowers  of  phosphorus). 
But  it  is  quite  certain  that  slight  volatilization  goes 
on  at  ordinary  temperature.  To  this  volatilization 


406  CHEMISTRY    SIMPLIFIED. 

is  probably  due  the  phosphorescence,  the  power  to  emit 
light  in  a  dark  room.  Surrounded  by  oxygen  alone 
there  is  no  phosphorescence ;  but  the  latter  pheno- 
menon appears  when  the  oxygen  is  diluted  with 
nitrogen.  Phosphorus  ignites  at  60°  C.  in  air. 
Rubbing  on  a  rough  surface  causes  ignition 
(matches).  Mixed  with  KC103  a  very  explosive 
substance  results  (lucifer  matches). 

Phosphorus  is  poison  to  man  and  animals  when 
brought  into  the  stomach  or  esophagus.  Every 
particle  of  the  phosphorus  causes  an  intense  local 
inflammation  of  the  membrane,  hence  great  pain 
and  shock,  which  result  in  death.  0.2  gram  may 
be  a  fatal  dose  for  an  adult  person.  Emptying  the 
stomach  by  emetics  and  the  pump  may  save  the  life 
in  some  cases.  The  workmen  in  match  factories  are 
known  to  suffer  from  necrosis  of  the  teeth,  the 
gums  and  the  jaw-bones  themselves.  Burns  made 
by  burning  phosphorus  on  the  fingers  have  even 
been  fatal.  Wash  out  such  wounds  with  utmost 
haste  with  a  dilute  water  solution  of  bleaching  lime, 
or  bleaching  soda  (crude  Javelle). 

The  best  solvent  for  the  active  form  of  phosphorus 
is  carbon  disulfid. 

(#).  Amorphous  red  phosphorus.  Sunlight,  espec- 
ially the  violet  portion  of  it,  or  heat  plus  pressure, 
or  the  electric  current,  changes  the  ordinary  phos- 
phorus more  or  less  rapidly  into  the  amorphous 
modification.  In  the  factories  the  change  is  brought 
about  by  keeping  the  yellow  phosphorus  for  10 
days  at  a  steady  temperature  of  260°  C. 


BONE- ASH  AND  PHOSPHORUS.         407 

The  amorphous  red  phosphorus  is  not  poisonous. 
It  does  not  melt  even  at  red  heat  but  volatilizes.  It 
is  not  soluble  in  CS2  nor  in  KOH.  It  appears  as 
a  scarlet  or  as  a  purplish-red,  pulverulent  mass, 
sometimes  brown-red.  In  bulk  it  shows  sometimes 
a  weak  metallic  luster,  more  often  no  luster  at  all. 
It  has  neither  taste  nor  odor,  does  not  show  phos- 
phorescence. It  ignites  at  260°  C.  Lt  forms  with 
KC103,  with  PbO2,  and  with  MnO2,  mixtures  which 
ignite  by  blows  or  friction.  It  is  the  only  phos- 
phorus now  used  in  matches,  or  on  the  friction  sur- 
faces of  safety  match  boxes. 

(3).  Black  crystallized  phosphorus.  By  heating 
red  phosphorus  in  a  vacuum  to  447°  C.  it  is  ob- 
tained as  a  violet-black  mass  of  conchoidal  fracture, 
or  by  fusing  together  in  a  vacuum  phosphorus  and 
metallic  lead.  After  cooling  one  finds  long-stretched 
rhombohedrons,  black  in  reflected  light,  red  in 
transmitted  light.  This  phosphorus  has  a  specific 
gravity  of  2.34. 

Atomic  weight  of  phosphorus,  P  =  31.  The  de- 
terminations of  the  vapor  density  lead  to  62.  We 
assume  therefore  that  the  element  in  the  free  state 
is  P2.  According  to  the  combinations  into  which 
phosphorus  enters  with  the  non-metals,  it  is  trivalent 
and  pentavalent  like  nitrogen. 

The  oxyds  of  phosphorus  are  P205,  P2O3. 

Phosphorus  pemtoxyd,  P205,  a  colorless,  vitreous 
solid  or  colorless  triclinic  crystals.  Dissolves  in 
water.  Is  very  hygroscopic  (goes  slowly  into  a 
syrup  when  standing  in  moist  air),  hence  it  is  often 


408  CHEMISTRY    SIMPLIFIED. 

used  to  dry  gases.  It  has  no  odor,  but  a  very  sour 
taste.  Is  sometimes  called  anhydrous  phosphoric 
acid.  Volatilizes  partly  at  250°  C.  But  when 
heated  quickly  it  changes  its  nature  by  polymeriza- 
tion (aggregation  of  molecules)  and  is  much  less 
volatile. 

Preparation.  By  igniting  phosphorus  in  a  flask 
in  a  current  of  perfectly  dry  air.  The  product  is  a 
mass  of  minute  snowy-white  crystals.  For  larger 
quantities  a  tinned  sheet-iron  cylinder  is  substituted 
for  the  flask. 

Phosphoric  acids.  It  was  Graham  who  first  de- 
monstrated that  the  pentoxyd  can  form  3  hydrates 
and  that  these  hydrates  possess  very  distinct  proper- 
ties. We  distinguish  these  hydrates  thus  :  The  tri- 
hydrate,  3H2O.P205,  the  dihydrate,  2H2O.P205 
and  the  monohydrate,  H2O.P205.  We  translate 
these  hydrates  into  the  radical  expressions  or  hydro- 
gen acids  thus : 

Trihydrate,  3H2O.P205  =  2H3(P04)  = 

orthophosphoric  acid. 
Dihydrate,  2H2O.P205  =  H4(T207)  = 

pyrophosphoric  acid. 
Monohydrate,  H2O.P205  =  2H(P03)  = 

metaphosphoric  acid. 

Orthophosphoric   acid,   HS(P04).     Orthorhombic, 
colorless  crystals,  or  a  thick  syrup  of  specific  gravity 
=  1.88.     Strong    acid    reaction ;  easily   soluble   in 
water.     Gives  green  coloration  to  a  flame. 

Preparation.     (I).  By  acting  with  UNO3  (specific 


BONE-ASH    AND    PHOSPHORUS.  409 

gravity  =  1.2)  upon  ordinary  phosphorus  in  a  glass 
retort,  (1  phosphorus,  10  acid),  at  such  a  tempera- 
ture that  lively  action  ensues,  but  not  a  violent  one, 
(because  explosions  may  set  in).  After  all  the 
phosphorus  has  disappeared  heat  to  boiling  and  dis- 
till over  about  7  parts  of  the  HNO3.  The  distillate 
has  a  specific  gravity  of  1.1-1.14  and  may  be  used 
for  another  operation  by  adding  enough  concen- 
trated acid  to  bring  gravity  up  to  1.2.  Pour  the 
liquid  from  the  retort  into  an  evaporating  dish 
and  evaporate  carefully  to  syrup,  or  until  all  HNO3 
has  been  removed.  Sometimes  there  occurs  during 
this  stage  another  disengagement  of  NO  from  the 
fact  that  some  P£03  is  still  present.  The  tempera- 
ture may  be  brought  to  188°  C.  but  not  higher,  for 
pyro-phosphoric  acid  may  form.  By  adding  some 
alcohol  the  remainder  of  HNO3  may  be  removed 
more  easily.  The  syrup  of  H3(P04)  is  called  glacial 
phosphoric  acid. 

(2).  By  acting  upon  red  amorphous  phosphorus 
with  concentrated  HNO3.  The  oxydation  is  more 
rapid  and  can  be  carried  on  in  a  beaker  glass. 

Orthophosphates.  The  orthophosphoric  acid  can 
form  3  series  of  salts  as  follows : 

Monads,  Na3(P04),  HNa2(P04),  H2Na(P04). 
Diads,  Ca3(P04)2,  Ca2H2(PO4)2,  CaH4(P04)2. 
Triads,  A13(P04)3,  A12H3(P04)3,  A1H6(P04)3. 

The  radical  (PO4)  is  trivalent,  hence  Na3(P04)  is 
a  fully  saturated  combination  and  so  is  A1(P04),  be- 
cause aluminum  is  trivalent.  But  in  order  to  bring 


"410  CHEMISTRY    SIMPLIFIED. 

out  the  partially  saturated  series  (A12H3)  and 
(A1H6),  we  must  treble  the  saturated  molecule  into 
A13(P04)3.  Any  diad  "metal  will  form  orthophos- 
phates  similar  to  calcium.  For  example,  copper  will 
make  Cu3(P04)2,  Cu2H2(P04)2,  CuH4(P04)2.  The 
three  series  are  sometimes  called  basic,  neutral,  acid.^ 
Cu3(P04)2  is  basic  copper  orthophosphate. 

Cu2H2(P04)  is  neutral  copper  orthophosphate. 
CuH4(P04)is  acid  copper  orthophosphate. 

The  orthophosphates  of  potassium,  sodium,  am- 
monium are  all  soluble  in  water  and  all  can  be 
crystallized.  The  most  common  of  them,  because 
most  easily  obtainable,  is  Na2H(P04)  +  12H20  in 
inonoclinic  crystals,  and  H.NH4.Na(P04)  +  4H20, 
also  inonoclinic  crystals.  The  latter  salt  goes  under 
the  names  :  salt  of  phosphorus,  and  microcosmic  salt. 
This  salt  fuses  into  a  perfect  glass  and  dissolves  at 
red  heat  most  of  the  metallic  oxyds,  giving  with  some 
of  them  transparent  glasses  of  constant  color.  Hence 
we  utilize  this  salt  as  a  flux  in  blow-pipe  analysis. 

Preparation  of  microcosmic  salt.  Dissolve  353 
grams  of  the  crystals  of  Na2HP04  +  12H20  and 
53.5  grams  of  NH4C1  (sal  ammoniac)  in  1700  c.c.  of 
warm  water,  filter  and  evaporate  until  a  film  of 
crystals  forms  at  the  surface.  Let  stand  for  several 
days  in  a  cool  place.  A  large  crop  of  the  micro- 
cosmic  salt  will  have  been  formed.  Drain  crystals 
from  mother  liquor.  Dissolve  again  in  water  and 
crystallize,  repeating  the  recrystallization  twice. 
Then  you  will  have  crystals  sufficiently  free  from 
NaCl  to  answer  for  blow-pipe  work.  Reaction  : 


BONE- ASH  AND  PHOSPHORUS.         411 

Na2HP04  +  water  4-  NH4C1  =  NH4.NaHP04  + 

water  -f-  NaCl. 

Nad  remaining   in   the    crystals  causes  the  bead, 
after  fusion,  to  become  white  and  opaque. 

Insoluble  orthophosphates.  The  neutral  solutions 
of  all  the  metals  are  precipitated  by  adding  a  solu- 
tion of  any  alkali  phosphate*  (K,  Na,  NH4).  These 
precipitates  are  soluble  in  dilute  acids — even  acetic 
acid.  Two  of  these  precipitates  are  of  special  inter- 
est because  by  means  of  them  we  distinguish  ortho- 
phosphoric  acid  from  other  acids. 

(1).  Silver  orthophosphate,  Ag*(PO*),  a  yellow  floc- 
culent  precipitate.  The  solution  must  be  neutral 
before  AgNO3  is  added  to  the  unknown. 

(#).  Ammonium-magnesium  orthophosphate,NH*.Mg- 
(PO4),  a  colorless,  granular  or  crystalline  precipitate 
which  forms  when  MgCl2  or  MgSO4  solution  is 
added  to  a  slightly  ammoniacal  solution  of  an  ortho- 
phosphate. 

The  most  delicate  or  sensitive  reagent  for  ortho- 
phosphate  is  the  so-called  molybdic  solution.  This  is 
a  solution  of  (NH4)2Mo04 — ammonium  molybdate 
—in  HNO3,  specific  gravity  1.2;  the  solution  is 
pale  yellow  or  colorless.  Any  metallic  phosphate 
is  first  dissolved  in  a  little  HNO3,  or  any  unknown 
substance  is  heated  with  HNO3,  water  added  and 
after  filtering  1  volume  of  the  molybdic  solution  is 
added.  The  temperature  of  the  liquid  is  brought 
to  about  50°  C.,  and  the  liquid  shaken  rapidly.  A 
fine  granular,  citron-yellow  precipitate  falls  if  a 
phosphate  be  present.  The  precipitate  is  (NH4)2- 


412  CHEMISTRY    SIMPLIFIED. 

H(P04).10Mo03  +  1JH20  =  ammonium-hydrogen 
phosphopolymolybdate. 

Pyrophosphoric  acid,  H*(P*07),  is  not  known  in 
solid  state,  only  known  as  an  aqueous  solution. 

Preparation.  Heat  the  salt  Na2H(P04)  -j-  12aq. 
in  a  crucible  until  all  the  water  is  driven  out  and 
then  to  redness  for  a  short  time.  Reaction  : 

2Na2H(P04)  +  heat  ==  Na4P207  +  H20. 

Dissolve  in  water  without  heating.  To  solu- 
tion add  PbA2  (lead  acetate) ;  a  white  precipitate 
Pb2(P207)  falls.  Filter  and  wash.  Suspend  the 
precipitate  in  water  and  pass  H2S  into  the  liquid  ; 
then  you  obtain  Pb2(P207)  -f  2H2S  =  2PbS  -f 
H4(P407),  which  are  separated  by  filtering. 

Properties.  (1).  When  the  acid  is  neutralized 
with  NH4OH  and  AgNO3  is  added,  a  white  floccu- 
lent  precipitate  falls  (not  yellow  as  with  an  ortho- 
phosphate).  (2).  MgCl2  does  not  produce  a  precip- 
itate. 

When  the  precipitate  MgNH4(P04)  (see  above)  is 
ignited  Mg2(P207)  magnesium  pyrophosphate  is 
left  behind.  A  solution'  of  pyrophosphoric  acid 
reverts  into  orthophosphoric  acid  by  boiling  for 
several  hours. 

Metaphosphoric  acid,  H(P03).  A  colorless  glassy 
substance. 

Preparation.  (1)  By  dissolving  P205  in  cold 
water.  (2)  By  heating  the  syrup  of  H3P04,  thus 
H3P04  +  heat  =  H20-f  H(P03).  (3)  By  fusing 
the  microcosmic  salt  at  a  red  heat  we  get 


BONE- ASH    AND    PHOSPHORUS.  413 

Na(NH4)H(P04)  -f  heat  =  Na(P03)  +  NH3  +  H20 
sodium  metaphosphate  +  ammonia  -f-  water.  The 
characteristics  of  metaphosphoric  acid  are  as  fol- 
lows :  (a)  the  acid  solution  causes  coagulation  (curd- 
ling) in  a  water  solution  of  albumen.  (Neither 
ortho-  nor  pyrophosphoric  acid  coagulates  the  albu- 
men.) (b)  When  the  solution  is  neutralized  with 
NH4HO,  AgNO3  solution  gives  a  white  gela- 
tinous precipitate,  (c)  When  a  solution  of  Na(P03) 
is  added  to  neutral  salts  of  the  metals,  a  precipitate 
forms  at  first,  but  dissolves  on  further  addition  of 
the  metaphosphate.  Some  of  the  precipitates  sepa- 
rate like  tough  resin,  some  separate  as  oily  liquids. 

Phosphorus  trioxyd,  P20S.  White  snowy  aggre- 
gates of  small  crystals  often  in  the  shape  of  trees 
or  ferns. 

Preparation.  Heat  phosphorus  in  a  tube  until  it 
ignites,  and  allow  a  very  slow  current  of  dry  air  to 
pass  through  the  tube.  The  oxyd  sublimes  into  a 
receiver.  In  the  dark  it  remains  unchanged.  Sun- 
light brings  red  or  orange  colors.  In  warm  oxygen 
it  ignites  and  changes  to  P205. 

It  smells  like  phosphorus.  Some  authors  say  it 
is  poisonous,  others  say  it  is  not ;  I,  myself,  think  it 
is  poisonous.  Very  slightly  soluble  in  water. 

Phosphorous  acid,  hydrogen  phosphite,  H*(POS). 
Crystalline-white  mass  or  distinct  crystals.  Soluble 
in  water.  Sour  taste.  Is  a  strong  deoxydixing 
agent.  In  salts  of  gold,  silver,  copper,  mercury,  the 
acid  causes  precipitation  of  the  metal. 

It  is  a  diatomic  acid,  that  is  to  say,  only  two  of 


414  CHEMISTRY    SIMPLIFIED. 

the  hydrogens  can  be  replaced  by  a  metal.  There 
are  therefore  two  series  of  phosphites,  Na2H(P03)  and 
NaH2.(P03). 

Preparation.     (1).  By  action  of  dilute  HNO3  upon 
phosphorus.     (2).  By  the  action  of  oxalic  acid  upon 
phosphorus  trichlorid.     Thus  : 
PC13  +  3H2.C204  =  H3P03-f  3HC1  +  3C02  +  SCO. 

Hypophosphorous  acid,  hydrogen  hypophosphite, 
H*P02.  A  colorless  substance  in  large  scales  or 
leaves.  Its  solution  in  water  is  even  more  deoxydiz- 
ing  than  the  preceding  phosphorous  acid.  It  is  a 
monobasic  acid.  Only  one  of  the  three  hydrogens 
can  be  replaced  by  a  metal.  Thus  NaH 2(PO 2)  or  still 
better  Na(HP02H)  =  sodium  hypophosphite,  or 
Ba(HP02H)2  =  barium  hypophosphite.  The  hypo- 
phosphites  have  been  recommended  as  very  active 
stimulants  of  the  nerves  and  the  brain  (humbug). 

Preparation,  3KHO+4P+3H20  =  3KH2P02-h 
PH3.  This  means  that  phosphorus  in  presence  of 
water  and  KHO  will  form  potassium  hypophosphite 
plus  phosphine  (PH3).  Ca(HO)2  and  Ba(HO)2  plus 
P  act  similarly. 

COMBINATIONS  OF  PHOSPHORUS  WITH  CHLORINE. 

Phosphorus  trichlorid,  PCI3.  Colorless  liquid. 
Produces  white  fumes  in  moist  air ;  refracts  the 
light  strongly,  smell,  penetrating,  and  the  vapor 
causes  tears  to  flow.  Boils  at  76°  C. 

When  PCI3  is  poured  into  cold  water  it  sinks  to 
the  bottom  and  collects  like  a  heavy  oil  ;  soon  a  re- 
action sets  up  between  the  water  and  the  chlorid, 


BONE-ASH    AND    PHOSPHORUS.  415 

PCI3  -f  3H20  =  H3.P03  +  3HC1,  the  result  being  a 
liquid  containing  phosphorous  acid  and  hydrochloric 
acid.  Such  a  solution  answers  as  a  deoxydizer. 

Preparation.  Place  in  a  retort  some  pieces  of  dried 
stick  phosphorus  (dry  with  blotting  paper),  the 
retort  having  been  previously  filled  with  CO2  gas. 
In  the  tubulus  fits  a  cork,  and  through  this  passes 
a  glass  tube  down  to  the  phosphorus.  A  receiver 
is  tightly  connected  with  the  retort,  and  is  well 
cooled.  Fill  now  the  retort  with  chlorine,  and 
warm  the  retort  until  the  phosphorus  melts,  when 
the  action  begins  and  PCI3  distills  over. 

Phosphorus pentachlorid,  PCI5.  A  colorless  solid. 
Peculiar  odor,  fumes  at  the  air.  With  little  water  it 
decomposes  into  HC1  and  POC13.  It  is  often  used 
in  synthetic  laboratory  work  to  put  Cl  into  complex 
molecules.  With  sodium  it  gives  2NaCl  -f  PCI8, 
and  the  same  with  other  metals.  With  much  water 
it  decomposes  into  phosphoric  acid  and  HC1. 

PCI5  -f-  4H20  =  5HC1  +  H3(P04),  orthophosphoric 

acid. 

Preparation.  By  acting  with  excess  of  Cl  upon 
PCI3.  There  are,  of  less  importance,  PBr3,  PBr5, 
PI3,  PI5,  PF5. 

Phosphine,  hydrogen  phosphid,  PH3.  A  gas  of 
disagreeable  odor,  somewhat  resembling  that  of 
garlic.  In  a  dark  room  the  gas  gives  out  a  pale 
light  like  phosphorus  itself.  It  causes  a  taste  on 
the^  tongue.  Sunlight  decomposes  the  gas  into 
hydrogen  and  red  amorphous  phosphorus.  The  gas 


416  CHEMISTRY    SIMPLIFIED. 

is  poisonous  because  the  blood  absorbs  it  like 
H(CN).  Air  containing  0.25  per  cent.  PH3  kills 
animals  in  5-10  minutes.  Phosphine  ignites  in  air 
at  149°  C.;  the  flame  is  white  and  yields  white 
smoke.  But  sometimes  the  gas  is  self -igniting.  This 
self-ignition  is  attributed  to  the  admixture  of  an- 
other compound  PH2,  which  latter  forms  only  under 
specific  conditions.  When  phosphine  gas  is  passed 
into  solutions  of  Ag,  Hg,  Cu,  Pb,  Bi,  Au  salts,  the 
metals  are  thrown  out ;  or  phosphids  of  the  metals 
are  formed.  PH3  in  a  solution  of  AgNO3  +  water 
causes  first  a  yellow  precipitate  of  Ag3P.3AgN03  (? 
doubtful  composition),  but  black  Ag3P  results  ulti- 
mately. 

Preparation.  (1).  Place  5-10  grams  of  stick  phos- 
phorus into  a  150  c.c.  flask.  Fill  the  flask  with 
KOH  solution  (1:5)  up  to  the  stopper.  The  latter 
carries  one  evolution  tube,  bent  so  that  it  can  be 
made  to  dip  under  water  in  a  dish  or  beaker  glass. 
(The  flask  is  to  be  filled  completely  to  avoid  ex- 
plosion with  air).  On  heating  the  flask  the  gas 
evolution  will  set  in,  and  if  the  water  in  the  dish  be 
warm,  each  gas  bubble  will  ignite  as  it  breaks  over 
the  water,  and  will  form  a  ring  of  smoke  in  the  air. 
(2).  Place  the  phosphorus  in  the  flask  as  before,  but 
fill  the  flask  with  an  alcoholic  solution  of  KOH.  (70 
per  cent,  alcohol.)  The  gas  will  not  ignite  by  itself. 
The  reason  for  this  is  that  the  self-igniting  PH2  re- 
mains dissolved  in  the  alcohol ;  does  not  mix  with 
the  gas  PH3.  In  both  these  actions  the  PH3  is 
generated  by  the  reaction 


BONE-ASH    AND    PHOSPHORUS.  417 

3KHO  +  4P  -f  3H20  =  PH3  +  3KH2P02. 
(3).  Prepare  Na3P  by  fusing  together  sodium  and 
phosphorus.     Or  by  fusing  together 

3Na2C03  +  Ca3(P04)2  -f  8Mg=  2Na3P  + 

3CaC03  +  8MgO. 

In  either  case  you  get  Na3Psand  if  a  drop  of  water 
touches  Na3P  then  phosphine  will  be  disengaged 
(noticed  by  strong  odor),  and  NaHO  will  form  : 

Na3P  -f-  3H20  =  PH3  +  3NaHO. 
Metallic  magnesium  can  be  carried  much  better 
than  sodium  because  it  does  not  oxydize  so  easily  at 
ordinary  temperature.  Hence  the  last  reaction  is 
the  one  best  adapted  to  test  an  unknown  mineral 
for  phosphorus,  in  the  field,  in  the  operation  of  blow- 
pipe analysis-.  We  call  it  the  phosphine  reaction. 
It  is  all  done  in  a  small  ignition  tube. 

Composition  of  PHZ.  Phosphine  breaks  up  read- 
ily at  a  red  heat  into  P  -f  H.  If  20  c.c.  of  phos- 
phine are  collected  over  mercury  in  a  eudiometer 
(see  ammonia)  and  the  spark  is  sent  through  it, 
complete  dissociation  results  in  from  6  to  10  minutes, 
when  the  volume  has  increased  to  30  c.c.  Phos- 
phorus covers  the  surface  of  the  tube  and  the  gas 
consists  entirely  of  hydrogen.  Now  since  the  vol- 
ume of  solid  phosphorus  is  so  small  as  to  be 
negligible  it  follows  that  20  c.c.  of  phosphine  con- 
tain 30  c.c.  of  hydrogen  and  10  c.c.  of  phosphorus 
gas.  Hence  PH3. 

Phosphonium,   PH4,   corresponds  to   ammonium, 
*>  and  is  only  known  hypothetically.     Because 
27 


418  CHEMISTRY    SIMPLIFIED. 

PH3  coriibines  by  simple  addition  with  HC1,  giving 
PH4Cl  (colorless  crystals  below  20°  C.). 

Liquid  hydrogen  phosphid,  PH2.  A  colorless 
liquid,  not  soluble  in  water.  In  contact  with  air 
ignites  instantaneously.  Forms  when  Ca3P2  is  de- 
composed with  H20  and  the  resulting  gas  is  carried 
through  a  U-tube  standing  in  the  freezing  mixture. 
At  the  same  time  with  the  liquid  PH2,  condenses  a 
solid  substance  which  has  probably  the  composition 
P2H.  Phosphorus  combines  directly  with  all 
metals,  yielding  metallic  phosphids.  Of  practical 
importance  are  the  phosphids  of  iron  (in  the  metal- 
lurgy of  iron  and  steel)  and  tin  phosphid,  Sn4P, 
beautiful  silver-white  crystals  (in  the  manufacture 
of  phosphorbronze). 


APPENDIX. 


THE    CHEMICAL    ELEMENTS,   THEIR   SYMBOLS,   EQUIVALENTS 
AND    SPECIFIC   GRAVITIES. 


Name.                           Symbol. 

Mass 
Unit 
Weight. 

Specific 
Gravity. 

Aluminium   AI. 
Antimony      ...        .    .                    Sb 

27.5 
122  0 

2.56 
6  70 

Arsenic  A.S 

75  0 

5  70 

Barium  i         Ba. 
Bismuth,                                               Bi 

137.0 
210  0 

4.00 
9  7 

Boron    B. 
Bromine                                               Br 

11.0 
80  0 

2.63 
5  54 

Cadmium  j         Cd. 
Caesium     j         Cs. 
Calcium         .    .            .                       Ca 

112.0 
133.0 
40  0 

8.60 
1.88 
1  58 

Carbon  ...                              j         C 

12  0 

3  50 

Cerium  1         Ce. 
Chlorine                                               Cl 

92.0 
35  5 

6.68 
2  45 

Chromium     Cr. 
Cobalt    ...                           Co 

52.5 

58  8 

6.81 

7  7 

Columbium                •                  I         Cb 

184  8 

6  00 

Copper           .                    .    .               Cu 

63  0 

8  96 

Didymium    ...                .               Di 

96  0 

6  54 

Erbium          .           E. 

1126 

— 

Fluorine    ......        .       >         F. 

19.0 

1.32 

Gallium     ;         Ga. 

69.9 

5.9 

Glucinuin                                    '         Gl 

9  5 

2  1 

Gold  (Aurum)  |         Au. 
Hydrogen  H. 
Indium         In 

196.0 
1.0 

113  4 

19.3 
0.069 
7.4 

Iodine    .            .                .    .               I 

127  0 

4  94 

Iridium      Ir 

198*0 

21.15 

56.0 

7.79 

90  2 

11  37 

Lead  (Plumbum)        .                       Pb 

207  0 

11  44 

Lithium    .....        •   •    .  j         Li 

7.0 

059 

(419) 


420 


APPENDIX. 


Name.                           Symbol. 

Atomic 
Weight. 

Specific 
Gravity. 

Magnesium                           .    .        •   Mg. 

24.0 
55.0 
200.0 
96.0 
58.8 
94.0 
14.0 
199.0 
16.0 
106.5 
31.0 
197.4 
39.0 
104.3 
85.4 
104.4 
79.5 
28.0 
108.0 
23.0 
87.6 
32.0 
1X2.0 
129.0 
204.0 
115.7 
118.0 
50.0 
184.0 
120.0 
51.3 
61.7 
65.0 
89.5 

1.75 
8.01 
13.59 
8.60 
8.60 
6.27 
0.972 
21.40 
1.105 
11.60 
1  83 
21.53 
0.865 
12.1 
1.52 
11.4 
4.78 
2.49 
10.5 
0.972 
254 
2.05 
1078 
6.02 
11.91 
7.8 
7.28 
4.3 
17.6 
18.4 
550 

7.14 
4.15 

Manganese            !         Mn. 
Mercury  (Hydrargyrum)  .    .  j         Hg. 
Molybdenum    ,         Mb. 
Nickel    Ni. 
Niobium    .        .                 ...            Nb. 
Nitrogen    N. 
Osmium  Os. 
Oxygen  O. 
Palladium                                .  *•         Pd. 

Phosphorus  .    .            ....            P. 
Platinum  |         Pt. 
Potassium  (Kalium)       ...           K. 
Rhodium  Ro. 
Rubidium  Rb. 
Ruthenium    I         Ru. 
Selenium   l         Se. 
Silicon       Si. 
Silver  (Argentum)                   .            Ag 

Sodium  (Natrium)  Na. 
Strontium  j         Sr. 
Sulphur        '  .                •                       S 

Tantalum  Ta. 
Tellurium  Te. 
Thallium  Tl. 
Thorium    Th. 
Tin  (Stannum)    j         Sn. 
Titanium  Ti. 
Tungsten  (Wolfram)  ....            W. 
Uranium   j         U. 
Vanadium     .        ....        .  1         V 

Yttrium.   .    .            Y. 
Zinc    '  .    .    .    .  j         Zn. 
Zirconium  Zr. 

TABLE  FOR  THE  COMPARISON  OF  THE  SCALES  OF  REAUMUR' S, 
CELSIUS'S,  AND  FAHRENHEIT'S  THERMOMETERS. 


Keaumur. 

Celsius. 

Fahrenheit. 

Reaumur. 

Celsius. 

Fahrenheit. 

—15 

—18.75 

_ 

33 

+41.25 

+106.25 

14 

17.50 

+0.50 

34 

42.50 

108.50 

13 

16.25 

2.75 

35 

43.75 

110.75 

12 

1500 

5.00 

36 

45.00 

113.00 

11 

13.75 

7.25 

37 

46.25 

115.25 

10 

12.50 

9.50 

38 

47.50 

117.50 

9 

11  25 

11.75 

39 

48.75 

119.75 

8 

10.00 

14.00 

40 

50.00 

122:00 

7 

8.75 

16.25 

41 

51.25 

124.25 

6 

7.50 

18.50 

42 

52.50 

126.50 

5 

6.25 

20.75 

43 

53.7* 

128.75 

4 

5.00 

23.00 

44 

55.00 

131.00 

3 

3.75 

25.20 

45 

56.25 

133.25 

2 

2.50 

27.50 

46 

57.50 

135.50 

+1 

1.25 

29.75 

47 

58.75 

137.75 

0 

0 

32.00 

48 

60.00 

140.00 

1 

+  1  25 

34.25 

49 

61.25 

142.25 

2 

2.50 

36.50 

50 

62.50 

144.50 

3 

3.75 

38.75 

51 

63.75 

146.75 

4 

5.00 

41.00 

52 

66.00 

149.00 

5 

625 

43.25 

5S 

66.25 

151  25 

6 

7.50 

45.50 

54 

67.50 

153.50 

7 

8.75 

47.75 

55 

68.75 

155.75 

8 

10.00 

50.00 

56 

70.00 

158.00 

9 

11.25 

52.22 

57 

71  25 

160.25 

10 

12.50 

54.59 

58 

72.50 

162.50 

11 

13.75 

56.75 

59 

73.75 

164.75 

12 

15.00 

59.00 

60 

75.00 

167.00 

13 

16.25 

61.25 

61 

76.25 

169.25 

14 

17.50 

63.50 

62 

77.50 

171.50 

15 

18.75 

65.75 

63 

78.75 

173.75 

16 

20.00 

68.00 

64 

80.00 

176.00 

17 

21.25 

70.25 

65 

81.25 

178  25 

18 

22.50 

72.50 

66 

82.50 

180.50 

19 

23.75 

74.75 

67 

83.75 

18275 

20 

25.00 

77.00 

68 

85.00 

185.00 

21 

26.25 

79.25 

69 

86.25 

187.25 

22 

27.50 

81.50 

70 

87.50 

189.50 

23 

28.75 

83-75 

71 

88.75 

191.75 

24 

30.00 

86.00     ! 

72 

90.00 

194.00 

25 

bl.25 

88.25 

73 

91.25 

196.25 

26 

32.50 

90.50     1 

74 

92.50 

198.50 

27 

33.75 

92.75 

75 

93.75 

200.75 

28 

35.00 

95.00 

76 

95.00 

203.00 

29 

36.25 

97.25 

77 

96.25 

205.25 

30 

37.50 

99.50 

78 

97.50 

207.50 

31 

38.75 

101.75 

79 

98.75 

209.75 

32 

40.00 

104.00 

80 

100.00 

212.00 

(421) 


422  APPENDIX. 

Rides  for  the  Conversion  of  the  Different  Thermometer 
Degrees  into  each  other. 

The  thermometers  referred  to  in  the  table  are  gradu- 
ated so  that  the  range  of  temperature,  between  the 
freezing  and  boiling  points  of  water,  is  divided  by 
Fahrenheit's  scale  into  180  (from  32°  to  212°)  by 
Celsius's  into  100  (from  0  to  100°),  and  by  that  of 
Reaumur  into  80  (from  0  to  80°)  portions  or  degrees. 

The  spaces  occupied  by  a  degree  of  each  scale  are 
consequently  as  1,  i  and  J  respectively,  or  as  1,  1.8 
and  2.25;  and  the  number  of  degrees  denoting  the  same 
temperature,  by  the  three  scales,  when  reduced  to  a 
common  point  of  departure  by  subtracting  32  from 
Fahrenheit's,  are  as  9,  5,  and  4.  Hence  we  derive  the 
following  equivalents  : 

A  degree  of  Fahrenheit  is  equal  to  0.5  of  Celsius's, 
or  to  0.4  of  Reaumur's;  a  degree  of  Celsius's  is  equal  to 
1.8  of  Fahrenheit's,  or  to  0.8  of  Reaumur's;  and  a  de- 
gree of  Reaumur's  is  equal  to  2.25  of  Fahrenheit's,  or 
to  1.25  of  Celsius's. 

To  convert  degrees  of  Fahrenheit  into  Celsius's  or 
Reaumur's,  subtract  32  and  multiply  the  remainder  by 
f  for  Celsius's,  or,  f  for  Reaumur's. 

To  convert  degrees  of  Celsius's  or  Reaumur's  into 
Fahrenheit's,  multiply  Celsius's  by  -f,  or  Reaumur's 
by  f ,  as  the  case  may  be,  and  add  32  to  the  product. 


APPENDIX.  423 

TABLE  OF  THE  LITER  WEIGHTS  OF  THE  GASES. 

Temp.  0°  C.  and  760  Mm.  Pressure. 

1  liter  of  air  weighs •    .   .    .  1.29300  Gms. 

"          CO.      "        1.25078  " 

•»<     •     CO2.     "        1.96500  " 

0.  "        ........  1.42910  " 

H.        "        0.08988  " 

N.        "        .    .    .    ._..  .    •    •  1.25070  " 

NO.      "        1.34260  '• 

NO2.    "               2.05440  " 

"          N2O,  "        1.96770  " 

"          NH3.  "            0.76170  " 

«          Cl.  "        3.17240  " 

"          HC1.  "        1.62850  *' 

H2S.  "        1.52100  '« 

"          SO2.  "        2.86150  " 

CH*.  "        0.71570  u 

steam*"        0.58960  " 

"          CaHJ.  4i        1.16200  " 

"          Br.  "        7.14259  " 

1.  "        11.27100  " 

S.  "        2.84300  " 

P.  »        5.63180  " 

Hg.  "           9.02100  " 

HI.  "        5.71067  <c 

HBr.  "        3.61607  " 

"          C2Na.   *'        2.32653     u 

*  At  100°  C.  and  760  Mm. 

The  values  in  the  above  table  may  be  calculated  from 
the  relation  between  the  molecular  weight  in  grams  of 
the  substance  and  its  liter  weight.  This  relation  may 
be  expressed  as  an  equation  thus  : 

weight  of  gram-molecule  =  congtant  =  22  38j 
weight  of  a  liter 

,.,           .  ,  ,        weight  of  gram  molecule, 
or  liter  weight  =          = °    ^ 


INDEX. 


ACETATE,  359 
Acid,  72,  124,  129 
abietinic,  379 
acetic,  278,  358 
carbolic,  282 
citric,  366 
cyanuric,  399 
formic,  305,  358 
fulminic,  400 
gallic,  368 
gluco-sulfuric,  343 
hydrobromic,  138 
hydrochloric,  108 
hydrofluoric,   148 
hydroiodic,  142 
hypophosphorous,  414 
lactic,  364 
malic,  366 

metaphosphoric,  412 
muriatic,  108 
nitric,  164 

orthophosphoric,  408 
oxalic,  361 
pan,  227 
phosphoric,  408 
phosphorous,  413 
picric,  282 
prussic,  395 
pyrogallic,  369 
pyroligneous,  276 
pyrophosphoric,  412 
sulfuric,  50,  52,  216    . 
tannic,  366 
tartaric,  364 

Air,  weight  of,  13 

Albumen,  blood,  386 
vegetable,  387 

Albumenoids,  387 

Alcohol,  346,  348 
absolute,  349 


i  Aldehyde,  354 

Alkali,  91 
;  Alkaline  reaction,  91,  187 

Alkaloids,  383 

Aluminum  reactions,  246 
j  Amalgam,  87 

Ammonia,  186.  190 

liquid,  200 
j  Ammonium,  194 
|  Amylum.  340 

Anilin,  321 

Anode,  26 

Anthracite,  308 
i  Aqua  fortis,  156 

regia,  156 
|  Arabin,  345 
'  Atom,  33 

|  Atomic  weights,  34,  126 
i  Atropin,  384 

BAKING  powders,  121 
Balsam.  378 
I  Base,  72,  129 
Benzene,  337 
Bleaching,  104 

lime,  104 
Bone-ash,  401 
black,  390 
!  Braise,  85 
Bromates,  139 
Bromine,  137 
Bromo  seltzer,  139 
Brucin,  384 
Butane,  303 

CAFFEIN,  383 
Calcite,  64 

!  Calcium  reactions,  252 
sulfid,  241 
tartrate,  365 


(425) 


426 


INDEX. 


Calcspar,  64 
Caoutchouc,  380 
Caps,  percussion,  356 
Carbamid,  389 
Carbon,  202,  257 

atomic  weight  of,  262 

dioxyd,  259 

disulfid,  254 

hydrates.  270 

monoxyd,  262 
Carbonates,  90 
Carboys,  113 
Casein,  388 
Cathode,  26 
Caustic  lime,  70 

soda,  122 

Cellulose,  264,  270,  305 
Chamber  acid,  227 
Charcoal,  animal,  389 

making,  274 
Charmotte,  85 

Chemical    elements,    their    sym- 
bols, equivalents,  and   specific 
gravities,  419,  420 
Chinin,384 
Chloral,  354 
Chlorates,  105,  135 
Chlorid,  silver,  111 
Chlorine,  98,  104 
Chloroform,  353 
Clay,  fire,  41 
Coal,  bituminous,  308 

brown,  309 

cannel,  309,  311 

distillation  of,  316 

hard,  308 

origin  of,  312 

-tar,  320 
Cocaine,  385 
Coke,  317 
Collodion,  272 
Colophony,  379 
Compounds,  16 
Copper  oxyd,  16,  47 

reactions,  250 
Copperas,  35 

action  of,  on  leather,  36 
Covellite,  234 
Creatinin,  388 
Cyanates,  394,  399 
Cyanids,  393 


Cyanogen,  396 

DECREPITATION,  93 
Deoxydation,  17 
Dextrin,  341 
Diamond,  257 
Dichloroxyd,  134 
Dichroism",  336 
Dissociation,  325 

Dynamite,  375 
/• 

EBONITE,  382 
Electrodes,  26 

Electrolysis,  25 

Electrolyte,  26 

Elements.  16 

their  symbols,  equivalents, 
and  specific  gravities,  419, 
420 

Endothermic  reaction,  330 

Etching.  149 

Ether,  352 

Ethylene,  324 

Eudiometer,  31 

Exothermic  reaction,  330 

TjUTS,  371 

-T      Fermentation,  199,  347 
Ferricyanates,  398 
Ferrocyanates,  392 
Fibrin,  388 
Fibroin,  389 
Fire-clay,  41 

Flash-point  of  an  oil,  337 
Fluorescin,  336 
Fluorids,  148 
Fluorine,  144,  150 
Fluorite,  144,  150 

gas,  146 
Fluorspar,  144 
Flux,  145 
Formate,  358 
Fuchsin,  322 
Fuel-gas,  333 
Fulminate,  355 
Fulminating  gas,  27 

riALENA,  181 

U     Galvani,  125 

Gangue,  144 

Gas,  analysis  apparatus  for,  285 


INDEX. 


427 


Gas,  fulminating,  27 

generator,  101,  103 

natural,  337 

works,  plan  of,  326 
Gases,  table  of  the  liter  weights 

of  the, 423 
Gasoline,  337 
Gay-Lussac  tower,  225 
Gelatine.  389 

blasting,  375 
Glass  ink,  150 
Glover  tower,  222 
Glucose.  343 
Glue,  389 
Gluten.  209,  339 
Glycerin,  374 

nitro-,  375 
Gold,  atomic-weight,  131 

chlorids.  131 

reactions,  246 
Graphite,  257 
Green  vitriol .  35,  36 
Gum  arabic,  345 
Gun-cotton,  271 

powder,  166 
Gutta-percha,  380 

HAEMATIN,  387 
Haemoglobin,  387 
Hair.  388 
Heat,  specific,  132 
Horn,  388 
Hydrates,  of  potassium,  79 

of  sulfuric  acid,  55 
Hydrogen.  25,  61 

chlorid.  107 

peroxyd,  34 

sulfate.  216 

sulfid,  234,  237,  253 
Hydrometer.  112 
Hydroxyd,  71 
Hydroxyl,   129 
Hypo,  243 
Hyposulfites,  243 
Hyssin,  388 

TOE,  19 

JL     Infusorial  earth,  375 

Ink,  36,  368 

lodates,  143 

lodids,  142 


Iodine,  139, 141 

and  starch.  141 
lodoform,  354 
lodyrite,  144 
Iron,  reactions  of,  246 
j  Isomerids,  303 

KELP,  122 
Kerosene,  337 
i  Knee  tube,  52 
Koenig  generator,  101 

i  T  ACTOSE,  345 
,  -L^     Laming5  s  mass,  328 
Laughing  gas,  182 
Law  of  combination  by  volume, 

134 

Dulong  and  Petit,  133 
Lead,  reactions  of.  246 
Leather,  368 
Leblanc  process,  119 
Levulose,  344 
Lignite,  309 
Lime,  burnt,  70 
caustic,  70 
gas,  66 
hydroxyd,  71 
Limestone.  65 
Litmus.  15 
Lunge- Rohrmann  plate  column, 

226 
Lye,  77 

MAGNESIUM,  137 
Manganese  chlorid,  100 

ore,  100 

Marsh  gas,  295,  301 
series,  302 
Mass  units,  33 
Mauvanilin.  321 
Mercury,  fulminate,  355 

reactions  of,  249 
Metals,  17 
i  Methane,  295 
Methylanilin,  321 
Microcosmic  salt,  410 
Molecular  weight,  55,  126,  132 
Molybdic  test  for  phosphates,  411 
Morphine,  209,  383 
;  Mortar,  75 
|  Mother  liquor,  137 


4'28 


INDEX. 


NAPTHALINE,  320 
Nascent  state,  186 
Natural  gas,  337 
Nicotine,  209,  385 
Niter,  152,  209,  211 

plantation,  210 
Nitrates,  164 

test  for,  178 
Nitrites,  179 
Nitro-benzol,  320 
cellulose,  271 
glycerin,  375 
Nitrogen,  154 

dioxyd,  171 

monoxyd.  176 

oxyds,  185 

weight  of,  13,  159 
Nitrose,  223 
Nitrous  fumes,  170 
Non-metals,  17 

OIL,  neat's  foot,  390 
ofDippel,  390 
vitriol,  230 
Oils,  370 
drying,  377 
essential,  371 
Olein,  377 
Orseille,  15 

Orthophosphates,  409,  411 
Oxybromids,  138 
-iodids,  143 
Oxyd, 16 

copper,  16,  47 
lead,  51 
Oxygen.  15,  31 
weight  of,  13 

PALMITIN,  377 
Papyrine,  270 
Paraffin,  283,  337 
Parchment,  270 
Pearlash,  77 
Peat,  309 
Pentane,  304 
Periodate,  143 
Peroxyd  of  hydrogen,  34 

sulfur,  47,  49 
Petroleum,  335 
ether,  337 


Thenol,  282 
Phosphids,  418 
Phosphine,  415 

reaction,  417 
Phosphites,  414 
Phosphonium,  417 
Phosphorbronze,  418 
Phosphorus,  black.  407 
pentachlorid,  415 
pentoxyd,  407 
red,  406 
trichlorid.  414 
trioxyd.  413 
yellow,  405 
Pitch,  380 

Plants,  structure  of,  265 
Platinum  stills,  228 
Polysulfids,  241 
Potash,  77 

bulb.  Liebig's,  267 

caustic,  79 
Potassium,  84 

chlorate.  105,  106 

hydroxyd,  79 

prussiate,  red,  398 
yellow,  391 

reactions,  249 
Propane,  303 
Protoplasm,  209,  258 
Prussian  blue,  391 
Putrefaction,  199 
Pyrite,  219 
Pyrogallol,  369 
Pyrolusite,  100 
Pyroxyline,  273 

AUININ,  384 

RADICAL,  124,  195 
Kectification,  350 
Kesin,  378 
Rock-oil,  335 

salt,  92 
Rosanilin.  322 
Eosin,  379 
Rubber,  380 

I  Rules  for  the  conversion  of  the 
different  thermometer  degrees 
I      into  each  other,  422 


INDEX. 


429 


SAFETY  lamp.  Davy's,  300 
Sal  ammoniac,  189,  197,  204 

soda,  121 
Salt,  72,  92,  129 
cake,  113 
gas,  94,  106 
of  phosphorus,  410 
seignette,  364 
Saltpetre,  152 
Saponification.  377 
Sarkin,  388 
Sericin,  389 
Series,  electrochemical.  125^ 

marsh  gas,  302 
Silk,  389 
Silver  chlorid,  111 

fulminate,  357 

reactions,  246 
Skin,  388 
Soap,  372,  377 

soft,  76 

Soda  ash.  119,  121 
Sodium,  116 

carbonate,  121 

reactions,  249 
Solar  oil,  281 
Soldering,  205 
Solvay  process,  206 
Spar/65 

Specific  heats,  132 
Spirits  of  niter,  155,  160 
salt,  94,  106 
Starch,  41,  340 
Stearin,  376 
Strychnine,  384 
Sugar,  342 

cane,  342 

fruit,  344 

grape,  343 

milk,  345 
Sulfid,  115 
Sulfocyanates,  397 
Sulfocyanogen,  397 
Sulfur,  13 

chlorid,  254 

oxyd,  16,  17,  52,  59 

peroxyd.  46,  49 

test  for,  40 
Superoxyd,  117 


TABLE  for  the  comparison  of 
the  scales  of  Reau- 
mur's, Celsius's  and 
Fahrenheit's  t  h  e  r  - 
mometers,  421 
of  the  liter  weights  of  the 

gases,  423 
iTaflow,376 
:  Tannin,  36.  366 
\  Tar,  coal,  320 
Tartar  emetic,  365 
Theobromin,  383 
,  Thermometers,  rules  for  the  con- 
version    of     the 
different   degrees 
of,      into       each 
other.  422 
table  for  the  com- 
parison    of     the 
scales    of    Reau- 
mur's,   Celsius's, 
and  Fahrenheit's, 
421 

Thiosulfates.  243 
Tin,  reactions,  246 
Toluidin,  323 
Turpentine,  378 

TTREA,  199,  383 

VALENCE,  125 
Varec,  122 
Vaseline,  337 
Vermilion.  234 
Vinegar,  15.  360 
Vitriol,  calcium,  73 

copper,  46 

green,  35,  36 

hydrogen.  129 

iron,  54,  58 

lead,  51 

oil  of,  40,  43,  50,  230 

silver,  49,  54 

zinc,  54 

Volume  weights,  126 
Vulcanizing,  382 


w 


ATER,  31 
-gas,  331 


430 


INDEX. 


Water,  hard,  74 

properties,  19 
Weights,  atomic,  34,  126 

molecular,  55,  126 

volume.  126 
Wood  distillation,  274 

gases,  285 

tar,  277,  279 


WooL  389 

VANTHINE,  388 
A. 


,  reactions,  246 


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an  Appendix  on  the  Coloring  of  Alloys  and  the  Recovery  of  Waste 
Metals.  By  WILLIAM  T.  BRANNT.  45  Engravings.  Third,  Re- 
vised, and  Enlarged  Edition.  570  pages.  Svo.  .  Net,  $5.00 

BRANNT.— The  Soap  Maker's  Hand-Book  of  Materials,  Processes 
and  Receipts  for  Every  Description  of  Soap.  Illustrated.  Svo.  (In 
preparation.) 

BEANS — A  Treatise  on  Railway  Curves  and  Location  of 

Railroads  : 
By  E.  W.  BEANS,  C.  E.     Illustrated.     I2mo.     Tucks.     .        $1.50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


BELL. — Carpentry  Made  Easy : 

Or,  The  Science  and  Art  of  Framing  on  a  New  and  Improved 
System.  With  Specific  Instructions  for  Building  Balloon  Frames,  Barn 
Frames,  Mill  Frames,  Warehouses,  Church  Spires,  etc.  Comprising 
also  a  System  of  Bridge  Building,  with  Bills,  Estimates  of  Cost,  and 
valuable  Tables.  Illustrated  by  forty-four  plates,  comprising  nearly 
200  figures.  By  WILLIAM  E.  BELL,  Architect  and  Practical  Builder. 

8vo. $5.00 

BEMROSE. — Fret-Cutting  and  Perforated  Carving: 

With  fifty-three  practical  illustrations.     By  W.  BEMROSE,  JR.     I  vol. 

quarto $2.50 

BEMROSE. — Manual  of  Buhl-work  and  Marquetry: 

With  Practical  Instructions  for  Learners,  and  ninety  colored  designs, 
By  W.  BEMROSE,  JR.     i  vol.  quarto  ....        $3.00 

BEMROSE.— Manual  of  Wood  Carving: 

With  Practical  Illustrations  for  Learners  of  the  Art,  and  Original  and 
Selected   Designs.     By  WILLIAM  BEMROSE,   JR.     With   an   Intro 
duction  by  LLEWELLYN  JEWITT,  F.  S.  A.,  etc.     With   128  illustra- 
tions, 4to.  ........        r         $2.50 

BERSCH.— Cellulose,  Cellulose  Products,  and  Rubber  Sub- 
stitutes : 

Comprising    the    Preparation    of    Cellulose,    Parchment-Cellulose, 
Methods  of  Obtaining  bugar,  Alcohol  and  Oxalic  Acid  from  Wood- 
Cellulose  ;     Production    of  Nitro-Cellulose    and   Cellulose    Esters ; 
Manufacture  of  Artificial  Silk,   Viscose,  Celluloid,   Rubber    Substi- 
tutes, Oil-Rubber,  and  Falctis.     By  DR.  JOSEPH  BERSCH.     Trans- 
lated by  WILLIAM  T.  BRANNT.    41  illustrations.     (1904.)     $3.00 
BILLINGS.— Tobacco : 

Its  History,  Variety,  Culture,  Manufacture,  Commerce,  and  Various 
Modes  of  Use.     By  E.   R.   BILLINGS.     Illustrated  by  nearly  200 
engravings.     8vo.      ........      $3.00 

BIRD.— The  American  Practical  Dyers'  Companion: 

Comprising  a  Description  of  the  Principal  Dye- Stuffs  and  Chemicals 
used  in  Dyeing,  their  Natures  and  Uses  ;  Mordants  and  How  Made  ; 
with  the  best  American,  English,  French  and  German  processes  for 
Bleaching  and  Dyeing  Silk,  Wool,  Cotton,  Linen,  Flannel,  Felt, 
Dress  Goods,  Mixed  and  Hosiery  Yarns,  Feathers,  Grass,  Felt,  Fur, 
Wool,  and  Straw  Hats,  Jute  Yarn,  Vegetable  Ivory,  Mats,  Skins, 
Furs,  Leather,  etc.,  etc.  By  Wood  Aniline,  and  other  Processes, 
together  with  Remarks  on  Finishing  Agents,  and  instructions  in  the 
Finishing  of  Fabrics,  Substitutes  for  Indigo,  Water-Proofing  of 
Materials,  Tests  and  Purification  of  Water,  Manufacture  of  Aniline 
and  other  New  Dye  Wares,  Harmonizing  Colors,  etc.,  etc.  ;  embrac- 
ing in  all  over  800  Receipts  for  Colors  and  Shades,  accompanied  by 
170  Dyed  Samples  of  Raw  Materials  and  Fabrics.  By  F.  J.  BIRD, 
Practical  Dyer,  Author  of  "  The  Dyers'  Hand-Book."  8vo.  $5.00 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE,, 


BLINN.— A  Practical  Workshop  Companion  for  Tin,  Sheet- 
Iron,  and  Copper-plate  Workers: 

Containing  Rules  Tor  describing  various  kinds  of  Patterns  used  by 
Tin,  Sheet-Iron  and  Copper- plate  Workers;  Practical  Geometry; 
Mensuration  of  Surfaces  and  Solids;  Tables  of  the  Weights  of 
Metals,  Lead-pipe,  etc. ;  Tables  of  Areas  and  Circumference* 
of  Circles ;  Japan,  Varnishes,  Lackers,  Cements,  Compositions,  etc.. 
etc.  By  LEROY  J.  BLINN,  Master  Mechanic.  With  One  Hundred 
and  Seventy  Illustrations.  121110.  .  .  .  .  .  $2.50 

BOOTH.— Marble  Worker's  Manual: 

Containing  Practical  Information  respecting  Marbles  in  general,  theii 
Cutting,  Working  and  Polishing ;  Veneering  of  Marble  ;  Mosaics ; 
Composition  and  Use  of  Artificial  Marble,  Stuccos,  Cements,  Receipts, 
Secrets,  etc.,  etc.  Translated  from  the  French  by  M.  L.  BOOTH. 
With  an  Appendix  concerning  American  Marbles.  I2mo.,  cloth  £1.50 

BRANNT.— A   Practical  Treatise  on  Animal  and  Vegetabll 

Fats  and  Oils  : 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chem- 
ical Properties  and   Uses,  the   Manner  of   Extracting  and   Refining 
them,  and  Practical  Rules  lor  Testing  them;  as  well  as  the  Manufac- 
ture of  Artificial  Butter  and  Lubricants,  etc.,  with  lists  of  American 
Patents  relating  to  the  Extraction,  Rendering,  Refining,  Decomposing, 
and  Bleaching  of  Fats  and  Oils.     By  WILLIAM  T.  BRANNT,  Editor 
of  the  "  Techno-Chemical  Receipt  Book."     Second  Edition,  Revised 
and  in  a  great  part  Rewritten."   Illustrated  by  302  Engravings.     In 
Two  Volumes.     1304  pp.  •  8vo.      .....        $10.00 

BRANNT.— A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science ; 
comprising  the  Chemistry,  Raw  Materials,  Machinery,  and  Utensils 
and  Various  Processes  of  Manufacture,  including  a  great  variety  of 
formulas.  Edited  chiefly  from  the  German  of  Dr.  C.  Deite,  A. 
Engelhardt,  Dr.  C.  Schaedler  and  others;  with  additions  and  lists 
of  American  Patents  relating  to  these  subjects.  By  WM.  T.  BRANNT. 
Illustrated  by  163  engravings.  677  pages.  8vo.  .  .  $12.50 

BRANNT. — India  Rubber,  Gutta-Percha  and  Balata  : 

Occurrence,  Geographical  Distribution,  and  Cultivation,  Obtaining 
and  Preparing  the  Raw  Materials,  Modes  of  Working  and  Utilizing 
them,  Including  Washing,  Maceration,  Mixing,  Vulcanizing, Rubber 
and  Gutta-Percha  Conpounds,  Utilization  of  Waste,  etc.  By  WILL- 
IAM T.  BRANNT.  Illustrated.  i2mo.  (1900.)  .  .  #3.00 


6  HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


BRANNT— WAHL.— The  Techno-Chemical  Receipt  Book  : 
Containing  several  thousand  Receipts  covering  the  latest,  most  im- 
portant,  and  most  useful  discoveries  in  Chemical  Technology,  and 
their  Practical  Application  in  the  Arts  and  the  Industries.  Edited 
chiefly  from  the  German  of  Drs.  Winckler,  Eisner,  Heintze,  Mier- 
zinski,  Jacobsen,  Roller  and  Heinzerling,  with  additions  by  WM.  T. 
BRANNT  and  WM.  H.  WAHL,  Ph.  D.  Illustrated  by  78  engravings. 
I2mo.  495  pages.  .......  $2.00 

BROWN. — Five  Hundred  and  Seven  Mechanical  Movements  : 
Embracing  all  those  which  are  most  important  in  Dynamics,  Hy- 
draulics, Hydrostatics,  Pneumatics,  Steam  Engines,  Mill  and  other 
Gearing,  Presses,  Horology,  and  Miscellaneous  Machinery  ;  and  in- 
cluding many  movements  never  before  published,  and  several  of 
which  have  only  recently  come  into  use.  By  HENRY  T.  BROWN. 
I2mo.  .........  $1.00 

BUCKMASTER. — The  Elements  of  Mechanical  Physics : 
By  J.  C.   BUCKMASTER.       Illustrated    with    numerous   engravings. 
I2mo.        .         .         .         .         .         .     "    .         .         .         .         $l.OQ 

BULLOCK. — The  American  Cottage  Builder  : 
A  Series  of  Designs,  Plans  and  Specifications,  from  $200  to  $20,000, 
for  Homes  for  the  People ;  together  with  Warming,  Ventilation, 
Drainage,  Painting  and  Landscape  Gardening.  By  JOHN  BULLOCK, 
Architect  and  Editor  of  "  The  Rudiments  of  Architecture  and 
Building,"  etc.,  etc.  Illustrated  by  75  engravings.  8vo. 

BULLOCK. — The  Rudiments  of  Architecture  and  Building: 
For  the  use  of  Architects,  Builders,   Draughtsmen,  Machinists,  En- 
gineers and  Mechanics.     Edited  by  JOHN  BULLOCK,  author  of  "  The 
American  Cottage  Builder."   Illustrated *by  250  Engravings.  8vo.$2.5o 

BURGH. — Practical    Rules    for    the   Proportions   of     Modern 

Engines  and  Boilers  for  Land  and  Marine  Purposes. 
By  N.  P.  BURGH,  Engineer.     I2mo.  ....         $1.50 

BYLES. — Sophisms    of    Free    Trade  and   Popular    Political 

Economy  Examined. 

By  a  BARRISTER  (SiR  JOHN  BARNARD  BYLES,  Judge  of  Common 
Pleas).  From  the  Ninth  English  Edition,  as  published  by  the 
Manchester  Reciprocity  Association.  I2mo.  .  .  .  $1.25 

BOWMAN.— The  Structure  of  the  Wool  Fibre  in  its  Relation 

to  the. Use  of  Wool  for  Technical  Purposes: 
Being  the  substance,  with  additions,  of  Five  Lectures,  delivered  at 
the  request  of  the  Council,  to  the  members  of  the  Bradford  Technical 
College,  and  the  Society  of  Dyers  and  Colorists.  By  F.  H.  BOW- 
MAN, D.  Sc.,  F.  R.  S.  E.,  F.  L.  S.  Illustrated  by  32  engravings. 
8vo #7.50 

BYRNE.— Hand-Book  for  the  Artisan,  Mechanic,  and  Engi- 
neer: 

Comprising  the  Grinding  and  Sharpening  of  Cutting  Tools,  Abrasive 
Processes,  Lapidary  Work,  Gem  and  Glass  Engraving,  Varnishing 
and  Lackering,  Apparatus,  Materials  and  Processes  for  Grinding  and 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


Polishing,  etc.  By  OLIVER  BYRNE.  Illustrated  by  185  wood  en- 
gravings. 8vo .  .  IjJ.oc 

3YRNE. — Pocket-Book  for  Railroad  and  Civil  Engineers: 
Containing  New,  Exact  and  Concise  Methods  for  Laying  out  Railroad 
Curves,  Switches,  Frog  Angles  and  Crossings ;  the  Staking  out  of 
work;  Levelling;  the  Calculation  of  Cuttings:  Embankments;  Earth- 
work, etc.  By  OLIVER  BYRNE.  i8mo.,  full  bound,  pocket-book 
form $1.50 

bYRNE. — The  Practical  Metal- Worker's  Assistant: 

Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all  Metals 
and  Alloys ;  Forging  of  Iron  and  Steel ;  Hardening  and  Tempering; 
Melting  and  Mixing;  Casting  and  Founding;  Works  in  Sheet  Metal; 
the  Processes  Dependent  on  the  Ductility  of  the  Metals ;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal* 
Workers.  With  the  Application  of  the  Art  of  Electro-Metallurgy  to 
Manufacturing  Processes;  collected  from  Original  Sources,  and  from 
the  works  of  Holtzapffel,  Bergeron,  Leupold,  Piumier,  Napier, 
ScorTern,  Clay,  Fairbairn  and  others.  By  OLIVER  BYRNE.  A  new, 
revised  and  improved  edition,  to  which  is  added  an  Appendix,  con- 
taining The  Manufacture  of  Russian  Sheet- Iron.  By  JOHN  PERCY, 
M.  D.,  F.  R.  S.  The  Manufacture  of  Malleable  Iron  Castings,  and 
Improvements  in  Bessemer  Steel.  By  A.  A.  FESQUET,  Chemist  and 
Engineer.  With  over  Six  Hundred  Engravings,  Illustrating  every 
Branch  of  the  Subject.  8vo.  .  -^'  -.  ....  $5.00 

BYRNE.— The  Practical  Model  Calculator: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work,  Naval 
Architect,  Miner  and  Millwright.  By  OLIVER  BYRNE.  8vo.,  nearly 
too  pages (Scarce.) 

CABINET  MAKER'S  ALBUM  OF  FURNITURE; 

Comprising  a  Collection  of  Designs  for  various  Styles  of  Fumitnrcu 
Illustrated  by  Forty-eight  Large  and  Beautifully  Engrav-d  Plates. 
Oblong,  8vo.  .  .  .  .  .-.-..  $1.50 

CALLINGHAM.— Sign  Writing  and  Glass  Embossing: 

A  Complete  Practical  Illustrated  Manual  of  the  Art.  By  JAMES 
CALLINGHAM.  To  which  are  added  Numerous  Alphabets  and  the 
Art  of  Letter  Painting  Made  Easy.  By  JAMES  C.  BADENOCH.  258 

pages,     ismo .        .         .        11.50 

"AMPIN. — A  Practical  Treatise  on  Mechanical  Engineering: 
Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools,  Work, 
shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Stean> 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Iron 
Ores.  By  FPANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention ;  with  a  Chapter  on  Explosions.  By  R, 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  (Scarce.) 


HENRY  CAREY  BAIRD  &  CG.'S  CATALOGUE. 


CAREY. — A  Memoir  of  Henry  C.  Carey. 
By  DR.  WM.  ELDER.    With  a  portrait.     8vo.,  cloth         .        .        75 

CAREY.— The  Works  of  Henry  C.  Carey : 

Harmony  of  Interests  :   Agricultural,  Manufacturing  and  Commer 

cial.     8vo.  .  $\.25 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  I  vol.  I2mo.  .  #2.00 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  $1000 

Past,  Present  and  Future.     8vo $2.50 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  #10.00 
The  Slave-Trade,  Domestic  and  Foreign;  Why  it  Exists,  and 
How  it  may  be  Extinguished  (1853).  8vo.  .  .  ,  $2.00 
The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental  and  Moral  Science  (1872).  8vo.  .  .  $2.50 

CLARK. — Tramways,  their  Construction  and  Working : 

Embracing  a  Comprehensive  History  of  the  System.  With  an  ex- 
haustive analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air;  a  description  of  the 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses.  By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  I  vol.  8vo.  .  $5.00 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man- 
agement. By  ZERAH  COLBURN.  Illustrated.  I2mo.  .  $1.00 

COLLENS.— The  Eden  of  Labor;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"   "The  Historj 
of  Charity,"  etc.     I2mo.     Paper  cover,  $1.00;  Cloth          .         #1.25 

COOLEY.— A  Complete  Practical  Treatise  on  Perfumery : 
Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Article! 
With   a  Comprehensive    Collection  of  Formulae.     By   ARNOLD   ' 
COOLEY.    i2mo $1.50 

COOPER.— A  Treatise  on  the  use  of  Belting  for  t\e  Trans- 
mission of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar- 
ranging Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten 
ings.  Examples  and  Rules  in  great  number  for  exhibiting  and  cal- 
culating the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Manigement  or 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  with 
chapters  on  the  Transmission  of  Power  by  Ropes;  by  Iron  and 
Wood  Frictional  Gearing ;  on  the  Strength  of  Belting  Leather ;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  B» 
JOHN  H.  COOPER,  M.  E.  8vo #3.50 

CRAIK.— The  Practical  American  Millwright  and  M^ler. 
By  DAVID  CRAIK,  Millwright.     Illustrated  by  numerous  wood  en~ 
gtavings  and  two  folding  plates.     8vo.       ...         .        .   (Scarce.) 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  9 

CROSS. — The  Cotton  Yarn  Spinner  : 

Showing  how  the  Preparation  should  be  arranged  for  Different 
Counts  of  Yarns  by  a  System  more  uniform  than  has  hitherto  been 
practiced;  by  having  a  .Standard  Schedule  from  which  we  make  all 
our  Changes.  By  RICHARD  CROSS.  122  pp.  I2mo.  .  75 

CRISTIANI. — A  Technical  Treatise  on  Soap  and  Candles: 
With  a  Glance  at  the  Industry  of  Fats  and  Oils.     By  R.  S.  CRIS- 
TIANI, Chemist.     Author  of  "  Perfumery  and  Kindred  Arts."     Illus- 
trated by  176  engravings.     581  pages,  8vo.  $15.00 

COURTNEY.— The  Boiler  Maker's  Assistant  in  Drawing, 
Templating,  and  Calculating  Boiler  Work  and  Tank 
Work,  etc. 

Revised  by  D.  K.  CLARK.     102  ilk,     Fifth  edition.  .        80 

COURTNEY.— The  Boiler  Maker's  Ready  Reckoner: 

With  Examples  of  Practical  Geometry  and  Templating.  Revised  by 
D.  K.  CLARK,  C.  E.  37  illustrations.  Fifth  edition.  •  $1.60 

DAVIDSON. — A  Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling,  and  Sign- Writing: 

Containing  full  information  on  the  processes  of  House  Painting  ic 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Principles  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  With  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A.  DAVIDSON.  i2mo. 

$2.00 

DAVIES.— A  Treatise  on  Earthy  and  Other    Minerals  and 

Mining: 

By  D.  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  etc.  Illustrated  by 
76  Engravings.  I2mo.  •  - $5.00 

DAVIES. — A  Treatise  on  Metalliferous  Minerals  and  Mining: 
By  D.  C.  DAVIES,  F.  G.  S  ,  Mining  Engineer,  Examiner  of  Mines, 
Quarries  and  Collieries.  Illustrated  by  148  engravings  of  Geological 
Formations,  Mining  Operations  and  Machinery,  drawn  from  the 
practice  of  all  parts  of  the  world.  Fifth  Edition,  thoroughly  Revised 
and  much  Enlarged  by  his  son,  E.  Henry  Davies.  I2mo.,  524 
pages .  $5.00 

DIETERICHS.— A  Treatise  on   Friction,  Lubrication,  Oils 

and  Fats : 

The  Manufacture  of  Lubricating  Oils,  Paint  Oils,  and  of  Grease,  and 
the  Testing  of  Oils.  By  E.  F.  DIETERICHS,  Member  of  the  Franklin 
Institute;  Member  National  Association  of  Stationary  Engineers; 
In ventor  of  Dieterichs' Valve-Oleum  Lubricating  Oik.  I2mo.  (1906.) 
A  practical  book  by  a  practical  man.  .  .  .  .  $1.2$ 

DAVIS.— A  Practical  Treatise  on  the  Manufacture  of  Brick, 

Tiles  and  Terra-Cotta : 

Including  Stiff  Clay,  Dry  Clay,  Hand  Made,  Pressed  or  Front,  and 
Roadway  Paving  Brick,  Enamelled  Brick,  with  Glazes  and  Colors, 
Fire  Brick  and  'Blocks,  Silica  Brick,  Carbon  Brick,  Glass  Pols.  R* 


jo          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGlJe,. 

torts,  Architectural  Terra-Cotta,  Sewer  Pipe,  Drain  Tile,  Glazed  and 
Unglazed  Roofing  Tile,  Art  Tile,  Mosaics,  and  Imitation  of  Intarsia 
or  Inlaid  Surfaces.  Comprising  every  product  of  Clay  employed  in 
Architecture,  Engineering,  and  the  Blast  Furnace.  With  a  Detailed 
Description  of  the  Different  Clays  employed,  the  Most  Modern 
Machinery,  Tools,  and  Kilns  used,  and  the  Processes  for  Handling, 
Disintegrating,  Tempering,  and  Moulding  the  Clay  into  Shape,  Dry- 
ing, Setting,  and  Burning.  By  Charles  Thomas  Davis.  Third  Edi- 
tion. .Revised  and  in  great  part  rewritten.  Illustrated  by  261 

engravings.     662  pages $20.00 

DAVIS. — A  Treatise  on  Steam-Boiler  Incrustation  and  Meth- 
ods for  Preventing  Corrosion  and  the  Formation  of  Scale: 
By  CHARLES  T.  DAVIS.     Illustrated  by  65  engravings.     8vo. 
DAVIS. — The  Manufacture  of  Paper : 

Being  a  Description  of  the  various  Processes  for  the  Fabrication, 
Coloring  and  Finishing  of  every  kind  of  Paper,  Including  the  Dif- 
ferent Raw  Materials  and  the  Methods  for  Determining  their  Values, 
the  Tools,  Machines  and  Practical  Details  connected  with  an  intelli- 
gent and  a  profitable  prosecution  of  the  art,  with  special  reference  to 
the  best  American  Practice.  To  which  are  added  a  History  of  Pa- 
per, complete  Lists  of  Paper-Making  Materials,  List  of  American 
Machines,  Tools  and  Processes  used  in  treating  the  Raw  Materials, 
and  in  Making,  Coloring  and  Finishing  Paper.  By  CHARLES  T. 
DAVIS.  Illustrated  by  156  engravings.  608  pages,  8vo.  $6.00 
DAVIS. — The  Manufacture  of  Leather: 

Being  a  Description  of  all  the  Processes  for  the  Tanning  and  Tawing 
with  Bark,  Extracts,  Chrome  and  all  Modern  Tannages  in  General 
Use,  and  the  Currying,  Finishing  and  Dyeing  of  Every  Kind  of  Leather; 
Including  the  Various  Raw  Materials,  the  Tools,  Machines,  and  all 
Details  of  Importance  Connected  with  an  Intelligent  and  Profitable 
Prosecution  of  the  Art,  with  Special  Reference  to  the  Best  American 
Practice.  To  which  are  added  Lists  of  American  Patents  (1884-1897) 
for  Materials,  Processes,  Tools  and  Machines  for  Tanning,,  Currying, 
etc.  By  CHARLES  THOMAS  DAVIS.  Second  Edition,  Revised,' and 
in  great  part  Rewritten.  Illustrated  by  147  engravings  and  14  Sam- 
ples oi  Quebracho  Tanned  and  Aniline  Dyed  Leathers.  8vo,  cloth, 

712  pages.     Price $12.1:0 

DAWIDOWSKY— BRANNT.— A  Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilac-es 
etc.: 

Eased  upon  Actual  Experience.  By  F.  DAWIDOWSKY,  Technical 
Chemist.  Translated  from  the  German,  with  extensive  addition^, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM  T.  BRANNT.  2d  revised  edition,  350  pages.  (1905.) 
Price  ....  3.,  o 

DE  GRAFF.— The  Geometrical  Stair-Builders*  Guide : ' 

Being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  it- 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Ste^ 
Engravings;  together  with  the  use  of  the  most  approved  pnncipi" 
of  Practical  Geometry  By  SIMON  DE  GRAFF,  Architect 


HENRY  CAREY   BAIRD   &  CO.'S  CATALOGUE.        il 

DE  KONINCK— DIETZ.— A  Practical  Manual  of  Chemical 

Analysis  and  Assaying : 

Asapplied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iroa, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DB 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.«  S.  G.,  M.  I.  C.  E.,  etc.  America* 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A, 
FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  .  Ji.oo 

DUNCAN.— Practical  Surveyor's  Guide: 

Containing  the  necessary  information  to  make  any  person  of  comj 
mon  capacity,  a  finished  land  surveyor  without  the  aid  of  a  teacher 
By  ANDREW  DUNCAN.  Revised.  72  engravings,  214 pp.  I2mo.  $1.50 

DUPLAIS. — A  Treatise  on  the   Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regan!  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grain,  Rice,  Potatoes,  Sorghum,  Aspho 
del,  Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Prepar?tion  of  Aro- 
matic Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  tbt 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copious 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc,,  etc.  Translated  and  Edited  from  the  French  of  MM.  DUPLAIS, 
By  M.  McKENNiE,  M.  D.  Illustrated  741  pp.  8vo.  £15.00 

DYER  AND  COLOR-MAKER'S  COMPANION  : 

Containing  upwards  of  two  hundred  Receipts  for  making  Colors,  on 
the  most  approved  principles,  for  all  the  various  styles  and  fabrics  novr 
in  evistence ;  with  the  Scouring  Process,  and  plain  Directions  for 
Preparing,  Washing-off,  and  Finishing  the  Goods.  I2mo.  $i  OO 

EIDHERR. — The  Techno-Chemical  Guide  to  Distillation: 
A  Hancl-Book  for  the  Manufacture  of  Alcohol  and  Alcoholic  Liquors, 
including  the  Preparation  of  Malt  and  Compressed  Yeast.     Edited 
from  the  German  of  Ed.  Eidherr. 

EDWARDS. — A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practical  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty  three  Engravings;  including  examples  of 
the  most  modern  Engines.  Third  edition,  thoroughly  revised,  with 
much  additional  matter.  12  mo.  414  pages  .  ^200 

EDWARDS. — Modern  American  Loccmotive  Engines, 
Their  Design,  Construction  and  Management.     By  EMORY  EDWARDS* 
Illustrated  I2mo $2.00 

EDWARDS.— The  American  Steam  Engineer: 
Theoretical  and  Practical,  with  examples  of  the  latent  and  most  ap- 
proved American  practice  in  the  design  and  construction  of  Steam 
Engines  and  Boilers.  For  the  use  of  engineers,  machinists,  boiler- 
umkers,  and  engineering  students.  By  EMORY  EDWARDS.  Fully 
illustrated,  419  pages.  I2mo.  -  ...  $2.00 


12        HENRY  CAREY  BAIRD  &  CO.'S   CATALOGUE. 

EDWARDS. — Modern  American  Marine  Engines,  Boilers,  and 

Screw  Propellers, 

Their  Design  and  Construction.     Showing  the  Present  Practice  ot 
the  most  Eminent  Engineers  and   Marine  Engine  Buildeis  in  the 
United  States.    Illustrated  by  30  large  and  elaborate  plates.  410.  $3.00 
EDWARDS. — The  Practical  Steam  Engineer's  Guide 
In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam   Pumps,  Boilers.  Injector^ 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and  Steam 
Gauges.     For  the  use  of  Engineers,  Firemen,  and  Steam  Users.    By 
EMORY  EDWARDS.     Illustrated  by   119  engravings.    A2o  pages'. 
I2ino.       ..........          $2.OO 

EISSLER.— The  Metallurgy  of  Silver : 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviation 
of  Silver  Ores,  including  the  Assaying,  Melting,  and  Refining  of 
Silver  Bullion.  By  M.  EISSLER.  124  Illustrations.  336  pp. 

I2mo #4-25 

ELDER. — Conversations  on  the  Principal  Subjects  of  Political 

Economy. 

By  DR.  WILLIAM  ELDER.    8vo.      ...  .        £2.00 

ELDER.— Questions  of  the  Day, 

Economic  and  Social.     By  DR.  WILLIAM  ELDER.     8vo.      .     $3.00 
ERNI  AND  BROWN.— Mineralogy  Simplified. 

Easy  Methods  of  Identifying  Minerals,  including  Ores,  by  Means  of 
the  Blow-pipe,  by  Flame  Reactions,  by  Humid  Chemical  Analysis, 
and  by  Physical  Tests.  By  HENRI  ERNI,  A.  M.,  M.  D.  Third  Edi- 
tion, revised,  re-arranged  and  with  the  addition  of  entirely  new  matter, 
including  Tables  for  the  Determination  of  Minerals  by  Chemical  and 
Pyrognostic  Characters,  and  by  Physical  Characters.  By  AMOS  P. 
BROWN,  E.  M.,  Ph.  D.  350  pp.,  illustrated  by  96  engravings,  pocket- 
book  form,  full  flexible  morocco,  gilt  edges  .  .  .  $2.50 
FAIRBAIRN.  -The  Principles  of  Mechanism  and  Machinery 

of  Transmission : 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pulleys, 
Strength  and  Proportion  of  Shafts,  Coupling  of  Shafts,  and  Engag- 
ing and  Disengaging  Gear.  By  SIR  WILLIAM  FAIRBAIRN,  Bart. 
C.  E.  Beautifully  illustrated  by  over  150  wood-cuts.  In  one 

volume,  I2mo $2.00 

FLEMING. — Narrow  Gauge  Railways  in  America  : 

A  Sketch  of  their  Rise,  Progress,  and  Success.  Valuable  Statistics 
as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  etc.  By 

HOWARD  FLEMING.     Illustrated,  8vo $1.00 

FORSYTH.— Book  of  Designs  for  Headstones,  Mural,  and 

other  Monuments  : 

Containing  78  Designs.     By  JAMES  FORSYTH,    With  an  Introduction 
by  CHARLES  BOUTELL,  M.  A.    410.,  cloth      .        .        .        #3.50 
FRIEDBERG.    Utilization  of  Bones  by  Chemical   Means- 
especially  the  Modes  of  Obtaining  Fat,  Glue,  Manures. 
Phosphorus  and  Phosphates. 
Illustrated.     8vo.     (In  preparation.) 


HENRY   CAREY   BAIRD  &  CO.'S  CATALOGUE.        13 


FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu- 
facture of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine: 
Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pest,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical 
Manufacturer  of  Starch-Sugar.  Illustrated  by  5$  engravings,  cover- 
ing  every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  $6.00 

GARDNER. — The  Painter's  Encyclopaedia: 
Containing  Definitions  of  all  Important  Words  in  the  Art  of  Plain 
and  Artistic  Painting,  with  Details  of  Practice  in  Coach,  Carriage, 
Railway  Car,  House,  Sign,  and  Ornamental  Painting,  including 
Graining,  Marbling,  Staining,  Varnishing,  Polishing,  Lettering, 
Stenciling,  Gilding,  Bronzing,  etc.  By  FRANKLIN  B.  GARDNER. 
158  Illustrations.  I2mo.  427  pp.  .  .  . ;s,.  i  .  Jte.oC 

GARDNER. — Everybody's  Paint  Book: 

A  Complete  Guide  to  the  Art  of  Outdoor  and  Indoor  Painting.  38 
illustrations.  L2mo,  183  pp.  .  .  .  .  ,  .  .  $l.oo 

GEE. — The  Jeweller's   Assistant  in  the   Art  of  Working  in 

Gold: 
A  Practical  Treatise  for  Masters  and  Workmen.     I2mo.     ;      $3.00 

GEE. — The  Goldsmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting,  and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste;  Chemical  and  Physical  Properties  of  Gold;  with  a  New 
System  of  Mixing  its  Alloys;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  .  .  $1.2$ 

GEE. — The  Silversmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of  Refining  and  Melting  the  Metal;  its 
Solders ;  the  Preparation  of  Imitation  Alloys ;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste ;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 
Memoranda.  By  GEORGE  E.  GEE.  Illustrated.  I2mo.  $1.25 

GOTHIC  ALBUM  FOR  CABINET-MAKERS: 

Designs  for  Gothic  Furniture.     Twenty-three  plates.     Oblong  $1-5° 

GRANT.— A  Handbook  on  the  Teeth  of  Gears  : 
Their  Curves,  Properties,  and  Practical  Construction.     By  GEORGE 
B.  GRANT.     Illustrated.     Third  Edition,  enlarged.     8vo.          $100 

GREENWOOD.— Steel  and  Iron: 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolling. 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN- 
WOOD, F.  C.  S.  With  97  Diagrams,  536  pages.  I2mo.  $1.75 


i4       HENRY  CAREY   BAIRD   &   CO.'S  CATALOGUE 

GREGORY. — Mathematics  for  Practical  Men : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  OLINTHUS  GREGORY.  8vo.,  plates  $3.00 

GKISWOLD. — Railroad  Engineer's  Pocket  Companion  for  th» 

Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En 
gi'neers;  also  the  Art  of  Levelling  from  Preliminary  Survey  to  ih< 
Construction  of  Railroads,  intended  Expressly  for  the  Young  En- 
gineer, together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  I2mo.,  tucks  ...  •  •  .  $^-S° 

GRUNER. — Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  oi 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines 
Translated,  with  the  author's  sanction,  with  an  Appendix,  by  L.  D. 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

Hand-Book  of  Useful  Tables  for  the  Lumberman,  Farmer  and 

Mechanic : 

Containing  Accurate  Tables  of  Logs  Reduced  to  Inch  Board  Meas. 
ure,  Plank,  Scantling  and  Timber  Measure;  Wages  and  Rent,  by 
Week  or  Month;  Capacity  of  Granaries,  Bins  and  Cisterns;  Land 
Measure,  Interest  Tables,  with  Directions  for  Finding  the  Interest  on 
any  sum  at  4,  5,  6,  7  and  8  per  cent.,  and  many  other  Useful  Tables. 
32  mo.,  boards,  ibo  pages .25 

HASERICK.— The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleaching  an/i  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yarm 
or  fabrics.  8vo.  ........  £>5-oo 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  Hatte* 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  $1.00 

HERMANN.— Painting  oil  Glass  and  Porcelain,  and  Enamel 

Painting: 

A  Complete  Introduction  to  the  Preparation  of  all  the  Colors  and 
Fluxes  Used  for  Painting  on  Glass,  Porcelain,  Enamel,  Faience  and 
Stoneware,  the  Color  Pastes  and  Colored  Glasses,  together  with  a 
Minute  Description  ot  the  Firing  ot  Colors  and  Enamels,  on  thf 
Basis  of  Personal  Practical  Experience  of  the  Art  up  to  Date.  18 
illustrations.  Second  edition. $4.00 

HAUPT. — Street  Railway  Motors: 

With  Descriptions  and  Cost  of  Plants  and  Operation  of  the  Varioui 
Systems  now  in  Use.  I2tw>.  ...  $1-75 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.        15 

HAUPT. — A  Manual  of  Engineering  Specifications  and  Con- 
tracts. 
By   LEWIS   M.  HAUPT,  C.   E.     Illustrated  with  numerous   maps. 

328pp.    8vo ,     ,...•';'    .        .        .        1300 

HAUPT. — The  Topographer,  His  Instruments  and  Methods. 
By  LEWIS  M.  HAUPT,  A.  M.,  C.  E.     Illustrated  with  numerous 
plates,  maps  and  engravings.     247  ppl    8vo.     .    '    .        .        $3.00 
HUGHES.— American  Miller  and  Millwright's  Assistant: 

By  WILLIAM  CARTER  HUGHES.    I2mo $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing  : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich;  the  Royal  Military  College,  Sandhurst ;  the  Indian  Civil  En- 
gineering College,  Cooper's  Hill ;  Indian  Public  Works  and  Tele- 
graph Departments ;  Royal  Marine  Li^ht  Infantry  ;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 

examples.     Small  quarto $1.00 

JEKVIS.— Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property ;  as  well  as  Railway  Manager-s,  ()ffi 
cers,  ar.d  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  the 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  £1.50 
KEENE.— A  Hand-Book  of  Practical  Gauging: 
For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla 
tion,  describing  the  process  in  operation  at  the  Custom- House  foi 
ascertaining  the  Strength  of  Wines.  By  JAMES  B.  KEENE,  of  H.  M. 

Customs.     8vo $loa 

KELLEY.— Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 

By  HON.  WILLIAM  D.  KELLEY.  M.  C.     544  pages,  8vo.  .        $2.50 
KOENIG.— Chemistry  Simplified: 

A  Course  of  Lectures  on  the  Non-Metals  Based  upon  the  Natural 
Evolution  of  Chemistry.  Designed  Primarily  for  Engineers.  By 
GEORGE  AUGUSTUS  KOENIG,  Ph.  D.,  A.  M.,  E.  M.,  Professor  of 
Chemistry,  Michigan  College  of  Mines,  Houghton.  Illustrated  by 
103  Original  Drawings.  449  pp.  I2mo.,  (1906).  .  .  $2.25 
KEMLO.— Watch- Repairer's  Hand-Book : 
Being  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apart, 
Putting  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  Foreign  Watches,  and  all  American  Watches.  By  F.  K£MLOP 
\acticalWatchmaker.  With  Illustrations.  lamo.  $1.25 


t6          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

KENTISH. — A  Treatise  on  a  Box  of  Instruments, 

And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Log* 
rithms,  including  Practical  Geometry,  Surveying,  Measuring  of  Tim- 
ber, Cask  and  Malt  Gauging,  Heights,  and  Distances.  By  THOMAS 
KENTISH.  In  one  volume.  I2mo.  ....  $I.OC 

KERL—  The  Assayer's  Manual: 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.  By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines.  Translated  from  the  German  by 
WILLIAM  T.  BRANNT.  Second  American  edition,  edited  with  Ex- 
tensive Additions  by  F.  LYNWOOD  GARRISON,  Member  of  the 
American  Institute  of  Mining  Engineers,  etc.  Illustrated  by  87  en- 
gravings. 8vo.  (Third  Edition  in  preparation. ) 

KICK.— Flour  Manufacture. 

A  Treatise  on  Milling  Science  and  Practice.  By  FREDERICK  KICK 
Imperial  Regierungsrath,  Professor  of  Mechanical  Technology  in  the 
imperial  German  Polytechnic  Institute,  Prague.  Translated  from 
the  second  enlarged  and  revised  edition  with  supplement  by  H.  H. 
P.  POWLES,  Assoc.  Memb.  Institution  of  Civil  Engineers.  Illustrated 
with  28  Plates,  and  167  Wood-cuts.  367  pages.  8vo.  .  $10.00 

KINGZETT.— The  History,  Products,  and  Processes  of  the 

Alkali  Trade : 

including  the  most  Recent  Improvements.    By  CHARLES  THOMAS 
Kfvr./ETT.  Consulting  Chemist.    With  23  illustrations.    8vo.       $2.50 
KIRK. — The  Cupola  Furnace: 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foundry 
Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter,  Con- 
sulting Expert  in  Melting.  Illustrated  by  78  engravings.  Second 
Edition,  revised  and  enlarged.  450  pages.  8vo.  1903.  $3-S° 

LANDRIN.— A  Treatise  on  Steel: 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.  From  the  French,  by  A.  A. 

FESQUET.     i2mo $2.50 

LANGBEIN.— A   Complete  Treatise  on  the  Electro-Deposi. 

tion  of  Metals : 

Comprising  Electro-Plating  and  Galvanoplastic  Operations,  the  De- 
position of  Metals  by  the  Contact  and  Immersion  Processes,  the  Color- 
ing of  Metals,  the  Methods  of  Grinding  and  Polishing,  as  well  as 
Descriptions  of  the  Electric  Elements.  Dynamo-Electric  Machines, 
Thermo-Piles  and  of  the  Materials  and  Processes  used  in  Every  De- 
partment  of  the  Ait.  From  the  German  of  DR.  GEORGE  LANGBEIN, 
with  additions  by  WM.  T.  BRANNT.  Fifth  Edition,  thoroughly  revised 
and  much  enlarged.  170  Engravings.  694  pages  8vq.  1905.  $4.00 

UARDNER. — The  Steam-Engine : 

For  the  Use  of  Beginners.     Illustrated.     I2mo.    .         .  60 

LEHNER.— The  Manufacture  of  Ink: 

<  •  Comprising  the   Raw  Materials,  and  the  Preparation  df  W^ting, 
Copying  and  Hektograph  Inks,  Safety  Inks,  Ink  Extracts  and  Pow- 

t   ders,  etc.     Translated  from  the  German  of  SlGMUND  LEHNER,  with 
additions  by  WILLIAM  T.  BRANNT.    Illustrated.     12010. 


•HENRY  CAREY    BAIRD  &  CO.'S  CATALOGUE.        17 

LARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide « 
A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  and 
their  Alloys,  etc.;  to  which  are  added  Recent  Improvements  in  thf 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  Bj 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  if 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  New  edition, 
revised,  with  extensive  additions.  414  pages.  1 20x0.  .  $2,50 

LEROUX. — A    Practical     Treatise    on    the    Manufacture    of 

Worsteds  and  Carded  Yarns  : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  the 
International  Jury,  and  of  the  Artisans  selected  by  the  Committed 
appointed  "by  the  Council  of  the  Society  of  Arts,  London,  on  Woolei 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni» 
versai  Exposition,  1867.  8vo.  $,4-°° 

LJEFFEL. — The  Construction  of  Mill-Dams : 
Comprising  also  the  Building  of  Race  and  Reservoir  Embankment! 
And  Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Water 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo. (Scarce.) 

LESLIE. — Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thousand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  I2mo.  ...  .  $1.50 

LE  VAN. — The  Steam  Engine  and  the  Indicator : 

Their  Origin  and  Progressive  Development;  including  the  Most 
Recent  Examples  of  Steam  and  Gas  Motors,  together  with  the  Indi- 
cator, its  Principles,  its  Utility,  and  its  Application.  By  WILLIAM 
BARNET  LE  VAN.  Illustrated  by  205  Engravings,  chisfly  of  Indi- 
cator-Cards. 469  pp.  8vo .  $2.00 

LIEBER. — Assayer's  Guide  ; 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
tfr  principal  Metals,  of  Gold  and  Silver  Coins  aad  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  Revised.  283  pp.  I2mo.  $1.50 

Cockwood's  Dictionary  of  Terms  : 

Used  in  the  Practice  of  Mechanical  Engineering,  embracing  those 
Current  in  the  Drawing  Office,  Pattern  Shop,  Foundry,  Fitting,  Turn- 
ing, Smith's  and  Boiler  Shops,  etc.,  etc.,  comprising  upwards  of  Six 
Thousand  Definitions.  Edited  by  a  Foreman  Pattern  Maker,  author 
>f  "  Pattern  Making."  417  pp.  I2mo.  .  .  . 


18         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE 

LUKIN.— The  Lathe  and  Its  Uses : 

Or  Instruction  in  the  Art  of  lurning  Wood  and  Metal.  Including 
&  Description  of  the  Most  Modern  Appliances  for  the  Ornamentation 
of  Plane  and  Curved  Surfaces,  an  Entirely  Novel  Form  of  Lathe 
for  Eccentric  and  Rose-Engine  Turning;  A  Lathe  and  Planing 
Machine  Combined;  and  Other  Valuable  Matter  Relating  to  the 
Art.  Illustrated  by  462  engravings.  Seventh  edition.  315  pages. 

Svo $4-25 

MAIN  and  BROWN.— Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And    Examination    Papers'    with    Hints    for    their   Solution.     B> 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal  ^aval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.    I2mo.,  cloth  .       $1.00 
MAIN  and  BROWN. — The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.  MAIN,   M.   A.  F.  R.,   Ass't    S.   Professor   Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineei 
R.  N.,  attached  to  the  R.  N.  College.     Illustrated.     Svo.  . 
MAIN  and  BROWN.— The  Marine  Steam-Engine. 
By  THOMAS  J.  MAIN,  F.  R.  Ass't  S.  Mathematical  Professor  at  the 
Royal    Naval    College,   Portsmouth,   and    THOMAS    BROWN,   Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.     Attached  to  the  Royal  Navai 
College.     With  numerous  illustrations.     Svo. 
MAKINS.— A  Manual  of  Metallurgy: 

By  GEORGE  HOGARTH  MAKINS.  100  engravings.  Second  edition 
rewritten  and  much  enlarged.  I2mo..  592  pages 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Mechanic^ 

Engineers  : 

Showing  the  Proper  Arrangement  of  iVheels  for  Cutting  the  Threads 
of  Screws  of  any  Required  Pitch;  with  a  Table  for  Making  the  Uni 
versal  Gas-Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 

Svo .50 

MICHELL.— Mine  Drainage: 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under 
rrcund  Steam  Pumping  Machinery.  With  a  Description  of  a  large 
number  of  the  best  known  Engines,  their  General  Utility  and  ih« 
Special  Sphere  of  their  Action,  the  Mode  of  their  Application,  and 
their  Merits  compared  with  other  Pumping  Machinery-  By  STEPHEN 
MICHKI.L.  Illustrated  by  247  engravings.  8 vo.,  369  pages.  $1250 
MOLESWORTH  —Pocket-Book  of  Useful  Formulae  and 
Memoranda  for  Civil  and  Mechanical  Engineers. 
By  GUILFORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Railway.  Full- 
bound  in  Pocket-book  form  . 


ilENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE          '9 

MOORE.— The  Universal  Assistant  and  the  Complete  Mi 
cnanit: 

Containing  over  one  million  Industrial  Facts,  Calculations,  Receipt^ 
Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
in  every  occupation,  from  the  Household  to  the  Manufactory.  Bj 
R.  MOORE.  Illustrated  by  500  Engravings.  I2mo.  .  £2.50 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks  : 
By  means  of  the  Prismoidal  Formula.  Illustrated  with  Numerouf 
Wood-Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas, 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyor^ 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork 
By  ELWOOD  MORRIS,  C.  E.  8vo $1.5* 

MAUCHLINE.— The  Mine  Foreman's  Hand-Book 

Of  Practical  and  Theoretical  Information  on  the  Opening,  Venti. 
lating,  and  Working  of  Collieries.  Questions  and  Answers  on  Prac- 
tical and  Theoretical  Coal  Mining.  Designed  to  Assist  Students  and 
Others  in  Passing  Examinations  for  Mine  Foremanships.  By 
ROBERT  MAUCHLINE.  3d  Edition.  Thoroughly  Revised  and  En- 
larged by  F.  ERNEST  BRACKETT.  134  engravings,  8vo.  378  pages. 
(W) ^3.75 

NAPIER.— A  System  of  Chemistry  Applied  to  Dyeing. 
By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Ed* 
tion.  Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar 'Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  oa  Dyeing  and  Calic« 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus- 
trated. Svo.  422  pages $2.50 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formula,  fo» 
finding  the  Discharge  of  Water  from  Orifices,  Notches 
Weirs,  Pipes,  and  Rivers : 

Third  Edition,  with  Additions,  consisting  of  New  Formulae  for  the 
>ischarge  from  Tidal  and  Flood  Sluices  and  Siphons;  general  infor 
nation  on  Rainfall,  Catchment-Basins,  Drainage,  Sewerage,  Wa;ei 
Supply  for  Towns  and  Mill  Power  Bv  TOHN  NEVTT.LK.  C.  E.  M  R 
I.  A. ;  Fellow  of  the  Royal  Geological  Society  of  Ireland.  Thid 

I2mo $5.5« 

4EWBERY.— Gleanings     from     Ornamental  •  Art    of    everj 

style : 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851.  and 
1862,  and  the  best  English  an'd  Foreign  works.  In  a  series  of  loo 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  By 
ROBERT  NEWBERY.  410.  »  .  .  .  %  y  .  (Scarce.) 

NICHOLLS.  -The  Theoretical  and  Practical  Boiler- Maker  and 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor 
Foremen  a*%i  Working  Boiler-Makers.  Iron,  Copper,  and  Tinsmiths 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


Iwaoghtsmen,  Engineers,  the  General  Steam-using  Public,  and  for  th» 
Use  of  Science  Schools  and  Classes.  By  SAMUEL  NICHOLLS.  Illu» 
trated  by  sixteen  plates,  I2mo. $2.50 

NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding : 
Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gilding,  and  Finishing.     Also,  the  Art  of  Marbling  Book-edges  and 
Paper.     By  JAMES  B.  NICHOLSON.     Illustrated.  I2mo.,  cloth     $2.25 

NICOLLS.— The  Railway  Builder: 

A  Hand-Book  for  Estimating  the  Probable  Cost  of  American  Rail- 
way Construction  and  Equipment.  By  WILLIAM  J.  NlCOLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form  .  $2.00 

NORMANDY.— The  Commercial  Handbook  of  Chemical  An- 

alysis : 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  01 
Commercial  Value  of  Substances  used  in  Manufactures,  in  Trades, 
and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
Co  a  great  extent  rewritten.  By  HENRY  M.  NOAD,  Ph.D.,  F.R.S., 
thick  I2mo Scarce 

NORRIS. — A  Handbook  fcr  Locomotive   Engineers  and  Ma 

chinists : 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco 
motives;  Manner  of  Setting  Valves;  Tables  cf  Squares,  Cubes,  Areas, 
etc.,  etc.  By  SEPTIMUS  NORRIS,  M.  E.  New  edition.  Illustrated, 
I2mo $i.5C 

NYSTROM.— A  New  Treatise  on  Elements  of  Mechanics : 
Establishing  Strict  Precision  in  the   Meaning  of  Dynamical  Terms 
accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me 
trology.     By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo. 

NYSTROM. — On  Technological  Education  and  the  Construe* 

tion  of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  Inn 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi 
tional  matter.  Illustrated  by  seven  engravings,  izmo.  .  $1.25 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 
Containing  a  brief  account  of  all  rhe  Substances  and  Processes]* 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  PractPc^ 
Receipts  and  Scientific  Information.     By  CHARLES  O'NEILL,  Anal>x 
tical  Chemist.     To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.     By  A.  A.  FESQUET» 
Chemist  and  Engineer.     With  an   appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,   1867-     8vo., 
491  pages  .  ."....  *2  50 

ORTON.— Underground  Treasures-. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
of  all  the  Useful  Minerals  within  the  United  States.  By  JAMES 
o*i\JK,  A.M.,  Late  Professor  of  Natural  H:story  in  Vassar  College, 
N.  Y  ;  author  of  the  "  Andes  and  the  Amazon,"  etc.  A  New  Edi- 
tion, with  An  Appendix  on  Ore  Deposits  and  Testing  Minerals  ( 


HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE.        21 

OSBORN. — The  Prospector's  Field  Book  and  Guide. 

In  the  Search  For  and  the  Easy  ^Determination  of  Ores  and  Other 
Useful  Minerals.  By  Prof.  H.  S.  OSBORN,  LL.  D.  Illustrated  by  66 
Engravings.  Seventh  Edition.  Revised  and  Enlarged.  379  pages, 

I2mo.     (March,  1907) $1.50 

OSBORN — A  Practical  Manual  of  Minerals,  Mines  and  Min- 
ing : 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and   Associations  of  the  Useful  Minerals;  their  Methods  of 
Chemical  Analysis  and  Assay  ;  together  with  Various  Systems  of  Ex- 
cavating and  Timbering,  Brick  and  Masonry  Work,  during  Driving, 
Lining,  Bracing  and  other  Operations,  etc.     By  Prof.  H.  S.  OSBORN, 
LL,  D.,  Author  of  «  The  Prospector's  Field- Book  and  Guide."     171 
engravings.     Second  Edition,  revised.     8vo.      .        .        .        £4.50 

OVERMAN.— The  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware, of  Slcel  and    Iron,  and  for  Men  of  Science  and  Art.     By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  lion,"  etc.     A  new,  enlarged,  and  revised  Edition.     By 
A.  A.  FESQbrr,  Chemist  and  Engineer.     I2mo.         .         .         $1.50 
3VERMAN.— The  Moulder's  and  Founder's  Pocket  Guide  : 
A  Treatise  on  Mouldingand  Founding  in  Green-sand,  Dry -sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow- 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues ;  Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals ;  Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.     By  FREDERICK  OVERMAN,  M.  E.     A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
Ordnance,  Malleable  Iron  Castings,  etc.     By  A.  A.  FESQUET,  Chen> 
ist  and  Engineer.     Illustrated  by  44  engravings.     I2mo.   .        £2.00 
PAINTER,  GILDER,  AND  VARNISHER'S  COMPANION. 
Comprising  the  Manufacture  and  Test  of  Pigments,  the  Arts  of  Paint- 
ing, Graining,  Marbling,  Staining,  Sign- writing,  Varnishing,  Glass- 
staining,  and  Gilding  on  Glass ;   together  with  Coach  Painting  and 
Varnishing,   and  the    Principles    of  the  Harmony  and  Contrast  of 
Colors.     Twenty-seventh  Edition.     Revised,  Enlarged,  and  in  great 
part  Rewritten.     By  WILLIAM  T.  BRANNT,  Editor  of  "  Varnishes, 
Lacquers,  Printing  Inks  and  Sealing  Waxes."     Illustrated.     395  pp. 
I2mo.       .         .         .         ,         .         .         .         .         .         .         $i  50 

PALLETT. — The  Miller's,  Millwright's,  and  Engineer's  Guide. 
By  HENRY  PALLETT.     Illustrated.     12010.       .        .        .        $2.00 


22          riENRY  CAREY   BAIRt)  &  CO.'S  CATALOGUE. 

PERCY. — The  Manufacture  of  Russian  Sheet-Iron. 

By  JOHN  PERCY,  M.  D.,  F.  R.  S.     Paper.       ....        25  cts, 
PERKINS.— Gas  and  Ventilation  : 

Practical  Treatise  on  Gas  and  Ventilation.     Illustrated.    I2mo.    $1.25 
PERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

and  Boiler  Plate  Roller  : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and  Piles 
to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron ;  the  Thickness  of  the  Bar  Gauge 
in  decimals;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  112  Ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 

$1.5° 

POSSELT. — Recent  Improvements  in  Textile  Machinery  Re- 
lating to  Weaving : 

Giving  the  Most  Modern  Points  on  the  Construction  of  all  Kinds 
of  Looms,  Warpers,  Beamers,  Slashers,  Winders,  Spoolers,  Reeds, 
Temples,  Shuttles,  Bobbins,  Heddles,  Heddle  Frames,  Pickers, 
Jacquards,  Card  Stampers,  etc.,  etc.  600  ill  us.  .  .  $3 .00 
POSSELT. — Technology  of  Textile  Design: 
The  Most  Complete  Treatise  on  the  Construction  and  Application 
of  Weaves  for  all  Textile  Fabrics  and  the  Analysis  of  Cloth.  By  E. 

A.  Posselt.     1,500  illustrations.     410 $5-OO 

POSSELT. — Textile  Calculations: 

A  Guide  to  Calculations   Relating  to  the  Manufacture  of  all  Kinds 
of  Yarns  and  Fabrics,  the  Analysis  of  Cloth,  Speed,  Power  and  Belt 
Calculations.     By  E.  A.  POSSELT.     Illustrated.    410.        .        $2.00 
REGNAULT. — Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  $6.00 
RICHARDS.— Aluminium : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illust.  Third  edition,  enlarged  and  revised  (1895)  .  $6.OO 
fclFFAULT,  VERGNAUD,  and  TOUSSAINT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors;  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessary  Apparatus  and  Directions  for  its  Use;  Dryers;  the 
Testing.  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
RIFFAULT,  VERGNAUD,  and  TOUSSA'INT.  Revised  and  Edited  by  M 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


F.  MALEPEYRE.   Translated  from  the  French,  by  A.  A. 

Chemist  and  Engineer.     Illustrated  by  Eighty  engravings.     In  one' 

vol..  "8vo.,  659  pages          .    '    ......        $5-°° 

ROPER.  —  Catechism  for  Steam  Engineers  and  Electricians: 
Including   the    Construction  and  Management   of   Steam    Engines, 
Steam  Boilers  and  Electric  Plants.     By  STEPHEN  ROPER.     Twenty- 
first  edition,  rewritten  and   greatly  enlarged  by  E.  R.  KELLER  and 
C.  W.  PIKE.     365  pages.     Illustrations.      i8mo.,  tucks,  gilt.     $2.00 

ROPER.—  Engineer's  Handy  Book: 

Containing  Facts,  Formulae,  Tables  and  Questions  on  Power,  its 
Generation,  Transmission  and  Measurement;  Heat,  Fuel,  and  Steam; 
The  Steam  Boiler  and  Accessories;  Steam  Engines  and  their  Parts; 
Steam  Engine  Indicator;  Gas  and  Gasoline  Engines;  Materials; 
their  Properties  and  Strength  ;  Together  with  a  Discussion  of  the  Fun- 
damenial  Experiments  in  Electricity,  and  an  Explanation  of  Dynamos, 
Motors,  Batteries,  etc.,  and  Rules  for  Calculating  Sizes  of  Wires.  By 
STEPHEN  ROPER.  I5ih  edition.  Revised  and  enlarged  by  E.  R. 
KELLER,  M.  E.  and  C.  W.  PIKE,  B.  S.  (1899),  with  numerous  illus- 
trations. Pocket-book  form.  Leather  .....  $3*5° 

ROPER.—  Hand-Book  of  Land  and  Marine  Engines  : 
Including  the  Modelling,  Construction,   Running,  and  Management 
of  Lane1  and  Marine  Engines  and  Boilers.     With  illustrations.     By 
STEPHEN  ROPER,  Engineer.    Sixth  edition.     I2mo.,rvcks,  gilt  edge. 

*3-5<J 
ROPER.—  Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion,   Management,   and    Running   of  Locomotives.     By   STEPHEN 
ROPER.     Eleventh  edition.     i8mo.,  tucks,  gilt  edge  .         £2.50 

ROPER.  —  Hand-Book  of  Modern  Steam  Fire-Engines. 
With  illustrations.     By  STEPHEN  ROPER,  Engineer.     Fourth  edition, 
I2mo.,  tucks,  gilt  edge       .......         $3-50 

ROPER.  —  Questions-  and  Answers  for  Engineers. 

This  little   book  contains  all   the  Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or- 
dinary intelligence  may  commit  them  to  memory  in  a  short  time.     By 
STEPHEN  ROPER,  Engineer.     Third  edition       .         .        .        $2.00 
ROPER.—  Use  and  Abuse  of  the  Steam  Boiler. 
By  STEPHEN  ROPER,  Engineer.     Eighth  edition,  with  illustrations. 
l8mo.,  tucks,  gilt  edge       .......        $2.00 

ROSE.—  The  Complete  Practical  Machinist  : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools 
Tool  Grinding,  Marking  out  Work,  Machine  Tools,  etc.  By  JOSHUA 
ROSE.  39^  Engravings.  Nineteenth  Edition,  greatly  Enlarged  with 
New  and  Valuable  Matter.  I2mo.,  504  pages.  .  .  $2.50 
ROSE.  —  Mechanical  Drawing  Self-Taught  : 

Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Tnstruments,  Elementary  Instruction  in  Practical  Mechanical  Draw- 


«4         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

ing,  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
Motions,  Engines  and  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  330  engravings.  8vo  ,  313  pages  ....  $4.00 

ROSE.— The  Slide- Valve  Practically  Explained: 

Embracing  simple  and  complete  Practical  Demonstrations  of  th> 
operation  of  each  element  in  a  Slide-valve  Movement,  and  illustrat- 
ing the  effects  of  Variations  in  their  Proportions  by  examples  care, 
fully  selected  from  the  most  recent  and  successful  practice.  By 
JOSHUA  ROSE,  M.  E.  Illustrated  by  35  engravings  .  $1.00 

ROSS. — The  Blowpipe  in  Chemistry,  Mineralogy  and  Geology: 
Containing  all  Known  Methods  of  Anhydrous  Analysis,  many  Work- 
ing Examples,  and  Instructions  for  Making  Apparatus.  By  LIEUT.- 
COLONEL  W.  A.  Ross,  R.  A.,  ,F.  G.  S.  With  120  Illustrations, 
I2mo $2.00 

SHAW.— Civil  Architecture : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building,  con- 
taining  the  Fundamental  Principles  of  the  Art.  By  EDWARD  SHAW, 
Architect.  To  which  is  added  a  Treatise  on  Gothic  Architecture,  etc. 
By  THOMAS  W.  SILLOWAY  and  GEORGE  M.  HARDING,  Architects. 
The  whole  illustrated  by  102  quarto  plates  finely  engraved  on  copper. 
Eleventh  edition.  4to. $6.00 

8HUNK. — A  Practical  Treatise  on  Railway  Curves  and  Loca- 
tion, for  Young  Engineers. 
By  W.  F.  SHUNK,  C.  E.    I2mo.    Full  bound  pocket-book  form  $2.00 

SLATER.— The  Manual  of  Colors  and  Dye  Wares. 
By  J.  W.  SLATER.     i2mo.        ......        $3.00 

SLOAN. — American  Houses  : 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  engravings,  with  descriptive  references.  By  SAMUEL 
SLOAN,  Architect.  8vo. .75 

SLOAN. — Homestead  Architecture  : 

Containing  Forty  Designs  for  Villas,  Cottages,  and  Farm-houses,  with 
Essays  on  Style,  Construction,  Landscape  Gardening,  Furniture,  etc., 
etc.  Illustrated  by  upwards  of  200  engravings.  By  SAMUEL  SLOAN, 
Architect.  8vo #2.50 

8LOANE. — Hoir>e  Experiments  m  Science. 
By  T.  O'CoNOR  SLCANE,  E.  M.,  A.  M.,  Fh.  D.     Illustrated  by  91 
engravings.     i2mo. $1.00 

SMEATON.— Builder's  Pockt^Companion : 

Containing  the  Elements  of  Building,  Surveying,  and  Architecture; 

with  Practical  Rules  and   Instructions  connected  with  the  subject. 

By  A.  C.  SMEATON,  Civil  Engineer,  etc.     I2mo. 
SMITH.— A  Manual  of  Political  Economy. 

By  E.  PESHINE  SMITH.     A  New  Edition,  to  which  is  added  a  full 

Index.     I2mo.  1 1  25 


HENRY  CAREY  BAlRD  &  CO.'S  CATALOGUE.          25 

SMITH.— Parks  and  Pleasure  -  Grounds : 

Or  Practical  Notes  on  Country  Residences,  Villas,  Public  Parks,  and 
Gardens.  By  CHARLES  H.  J.  SMITH,  Landscape  Gardener  and 
Garden  Architect,  etc.,  etc.  I2mo.  .=  .-  .  .  $2.00 

SMITH.— The  Dyer's  Instructor: 

Comprising  Practical  Insfuctions  in  the  Art  of  Dyeing  Silk,  Cotton, 
Wool,  and  Worsted,  and  Woolen  Goods ;  containing  nearly  800 
Receipts.  To  which  is  added  a  Treatise  on  the  Art  of  Padding;  and. 
the  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs,  and  th« 
various  Mordants  and  Colors  for  the  different  styles  of  such  work. 
By  DAVID  SMITH,  Pattern  Dyer.  I2mo.  .  .  .  $1.00 

SMYTH.— A  Rudimentary  Treatise  on  Coal  and  Coal-Mining. 
By  WARRINGTON  W.  SMYTH,  M.  A.,  F.  R.  G.,  President  R.  G.  S. 
of  Cornwall.  Fifth  edition,  revised  and  corrected.  With  ftumer- 
ous  illustrations.  I2mo. Si. 40 

SNIVELY.— Tables  for  Systematic  Qualitative  Chemical  Anal. 

ysis. 
By  JOHN  H.  SNIVELY,  Phr.  D.     8vo.        ....        $1.00 

SNIVELY.— The  Elements  of  Systematic  Qualitative  chemical 

Analysis : 

A  Hand-book  for  Beginners.    By  JOHN  H.  SNIVELY,  Phr.  D.    i6mo. 

$2.00 

STOKES. — The  Cabinet  Maker  and  Upholsterer's  Companion: 
Comprising  the  Art  of  Drawing,  as  applicable  to  Cabinet  Work; 
Veneering,  Inlaying,  and  Buhl- Work ;  the  Art  of  Dyeing  and  Stain 
ing  Wood,  Ivory,  Bone,  Tortoise-Shell,  etc.  Directions  for  Lacker- 
ing, Japanning,  and  Vanishing;  to  make  French  Polish,  Glues, 
Cements,  and  Compos:.i<-  ns ;  with  numerous  Receipts,  useful  to  work 
men  generally.  Bv  STOKES.  Illustrated.  A  New  Edition,  with 
an  Appendix  upor  ,ench  Polishing,  Staining,  Imitating,  Varnishing, 
etc.,  etc.  I2mo $1.25 

STRENGTH  AND  OTHER  PROPERTIES  OF  METALS; 

Reports  of  Experiments  on  the  Strength  and  other  Properties  of 
Metals  for  Cannon.  With  a  Description  of  the  Machines  for  Testing 
Metals,  and  of  the  Classification  of  Cannon  in  service.  By  Officer? 
of  the  Ordnance  Department,  U.  S.  Army.  By  authority  of  the  Secre- 
tary of  War.  Illustrated  by  25  large  steel  plates.  Quarto  .  $5.00 

SULLIVAN. — Protection  to  Native  Industry. 
By  Sir  EDWARD  SULLIVAN,  Baronet,  author  of  "  Ten  Chapters  on 
Social  Reforms."     8vo.     .         .         .         .         .         .         •         $l.OO 

SHERRATT.— The  Elements  of  Hand-Railing: 

Simplified  and  Explained  in  Concise  Problems  that  are  Easily  Under- 
stood. The  whole  illustrated  with  Thirty-eight  Accurate  and  Origi- 
nal Plates,  Founded  on  Geometrical  Principles,  and  Showing  how  to 
Make  Rail  Without  Centre  Joints,  Making  Better  Rail  of  the  Same 
Material,  with  Half  the  Lalx>r,  and  Showing  How  to  Lay  Out  Stairs 
of  all  Kinds.  By  R,  J.  SHERRATT.  Folio.  .  .  .  52.50 


26        HENRY  CAREY  BAIRr?  &  CO.'S  CATALOGUE. 


SYME.— Outlines  of  an  Industrial  Science. 
By  DAVID  SYME.     121110.       •   .  ...        $2.00 

TABLES     SHOWING     THE     WEIGHT  ,  OF     ROUND, 

SQUARE,  AND  FLAT  BAR  IRON,  STEEL,  ETC., 
By  Measurement.     Cloth  ......  63 

THALLNER.— Tool-Steel : 

A  Concise  Handbook  on  Tool-Steel  in  General.  Its  Treatment  In 
the  Operations  of  Forging,  Annealing,  Hardening,  Tempering,  etc., 
and  the  Appliances  Therefor.  By  OTTO  THALLNER,  Manager  in 
Chief  of  the  Tool-Steel  Works,  Bismarck hiitte,  Germany.  From  the 
German  by  WILLIAM  T.  BRANNT.  Illustrated  by  69  engravings. 
194  pages.  8vo.  1902.  ......  $2.00 

TEMPLETON. — The  Practical  Examinator  on  Steam  and  thd 

Steam-Engine: 

With  Instructive  References  rela'.ive  thereto,  arranged  for  the  Use  of 
Engineers,  Students,  and  others.  By  WILLIAM  TEMPLETON,  En. 
gineer.  I2mo.  ....•••.  $1.00 

THAU  SING.— The  Theory  and  Practice  of  the  Preparation  of 

Malt  and  the  Fabrication  of  Beer: 

With  especial  reference  to  the  Vienna  Process  of  Brewing.  Elab- 
orated from  personal  experience  by  JULIUS  E.  THAUSING,  Professor 
at  the  School  for  Brewers,  and  at  the  Agricultural  Institute,  Modling, 
near  Vienna.  Translated  from  the  German  by  WILLIAM  T.  BRANNT, 
Thoroughly  and  elaborately  edited,  with  much  American  matter,  and 
according  to  the  latest  and  most  Scientific  Practice,  by  A.  SCHWARZ 
and  DR.  A.  H.  BAUER.  Illustrated  by  140  Engravings.  8vo.,  815 
pages  ..........  $10.00 

THOMPSON. — Political  Economy.     With  Especial  Reference 

to  the  Industrial  History  of  Nations  : 

By  ROBERT  E.  THOMPSON,  M.  A.,  Professor  of  Social  Science  in  the 
University  of  Pennsylvania.  I2mo.  .  .  .  $1.50 

THOMSON.— Freight  Charges  Calculator: 

By  ANDREW  THOMSON,  Freight  Agent.     241110.         .         .         $1.25 

TURNER'S  (THE)  COMPANION: 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric  Turn, 
ing;  also  various  Plates  of  Chucks,  Tools,  and  Instruments;  and 
Directions  for  using  the  Eccentric  Cutter,  Drill,  Vertical  Cutter,  and 
Circular  Rest;  with  Patterns  and  Instructions  for  working  them. 
I2mo $I.oo 

TURNING :  Specimens  of  Fancy  Turning  Executed  on  the 

Hand  or  Foot- Lathe : 

With  Geometric,  Oval,  and  Eccentric  Chucks,  and  Elliptical  Cutting 
Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Photographs. 
4*0 (Scarce.) 


HENRY  CAREY  BAIRB  &  CO.'S  CATALOGUE.          vj 

VAILE. — Galvanized-Irog  Cornice-Worker's  Manual : 

Containing  Instructions  in  Laying  out  the  Different  Mitres,  and 
Making  Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also, 
Tables  of  Weights,  Areas  and  Circumferences  of  Circles,  and  other 
Matter  calculated  to  Benefit  the  Trade.  By  CHARLES  A.  VAILE, 
Illustrated  by  twenty-one  plates.  4to (Scarce.) 

VILLE.— On  Artificial  Manures : 

Their  Chemical  Selection  and  Scientific  Application  to  Agriculture. 
A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VlLLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 
engravings.  8vo.,  450  pages  .  .  ,  .  .  .  $6.00 

VILLE. — The  School  of  Chemical  Manures : 
Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.     From 
the  French  of  M.  GEO.  VILLE,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer.    With  Illustrations.     I2mo.  .         .        .        .        $1.2$ 

VOGDES.— The  Architect's  and  Builder's  Pocket- Companion 

and  Price-Book: 

Consisting  of  a  Shoit  but  Comprehensive  Epitome  of  Decimals,  Duo- 
decimals, Geometry  and  Mensuration ;  with  Tables  of  United  States 
Measures,  Sizes,  Weights,  Strengths,  etc.,  of  Iron,  Wood,  Stone, 
Brick,  Cement  and  Concretes,  Quantities  of  Materials  in  given  Sizes 
and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
Bills  of  Prices  for  Carpenter's  Work  and  Painting;  also,  Rules  for 
Computing  and  Valuing  Brick  and  Brick  Work,  Stone  Work,  Paint- 
Ing,  Plastering,  with  a  Vocabulary  of  Technical  Terms,  etc.  By 
FRANK  W.  VOGDES,  Architect,  Indianapolis,  Ind.  Enlarged,  revised, 
and  corrected.  In  one  volume,  368  pages,  full-bound,  pocket-book 

form,  gilt  edges $2.00 

Cloth         .  1.59 

VAN  CLEVE.— The  English  and  American  Mechanic: 
Comprising  a  Collection  of  Over  Three  Thousand  Receipts,  Rules, 
and  Tables,  designed  for  the  Use  of  every  Mechanic  and  Manufac- 
turer. By  B.  FRANK  VAN  CLEVE.  Illustrated.   500  pp.  I2mo.  52.00 

VAN  DER  BURG.— School  of  Painting  for  the  Imitation  of 

Woods  and  Marbles: 

A  Complete,  Practical  Treatise  on  the  Art  and  Craft  of  Graining  and 
Marbling  with  the  Tools  and  Appliances.  36  plates.  Folio,  12  x  20 
inches.  .  .  •"?«.-•:  .  «*.  *  .  •  •  •  $6.00 

WAHNSCHAFFE.— A  Guide  to  the  Scientific  Examinatioa 

of  Soils: 

Comprising  Select  Methods  of  Mechanical  and  Chemical  A  lalysi* 
and  Physical  Investigation.  Translated  from  the  German  of  Dr.  F. 
WAHNSCHAFFE.  With  additions  by  WILLIAM  T.  BRANNT.  Illus- 
trated by  25  engravings.  121110.  177  pages  .  .  .  $1.50 

IV ALTON-— Coal-Mining  Described  and  Illustrated: 
By  THOMAS  H.  WALTON,  Mining  Engineer.     Illustrated  by  24  ?argi 
and  elaborate  Plates,  after  Actual  Workings  and  Apparatus.     $ 2.00 


2'v          HENRY  CAREY  BAIRD  &  CO.'S  CATALOC  UE, 

WARE.— The  Sugar  Beet. 

Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varietie 
of  the  Sugar  Beet,  Examination,  Soils,  Tillage,  Seeds  and  Sowing 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserva 
tion,  Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWH 
S.  WARE,  C.  £.,  M.  E.  Illustrated  by  ninety  engravings.  8vo. 

$3-50 

WARN. — The  Sheet-Metal  Worker's  Instructor: 

For  Zinc,  Sheet- Iron,  Copper,  and  Tin- Plate  Workers,  etc.  Contain- 
ing a  selection  of  Geometrical  Problems ;  also,  Practical  and  Simple 
Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin- Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty- 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  .  $2.50 

WARNER.— New  Theorems,  Tables,  and  Diagrams,  for  tht 
Computation  of  Earth-work : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profes- 
sional Computers.  In  two  parts,  with  an  Appendix.  Part  I.  A  Prac- 
tical Treatise;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix. 
Containing  Notes  to  the  Rules  and  Examples  of  Part  I.;  Explana 
tions  of  the  Construction  of  Scales,  Tables,  and  Diagrams,  and  a 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights 
By  JOHN  WARNER,  A.  M.,  Mining  and  Mechanical  Engineer.  Illus- 
trated by  14  Plates.  8vo.  ......  $3.00 

WILSON.— Carpentry  and  Joinery  : 

By  JOHN  WILSON,  Lecturer  on  Building  Construction,  Carpentry  and 
Joinery,  etc.,  in  the  Manchester  Technical  School.  Third  Edition, 
with  65  full-page  plates,  in  flexible  cover,  oblong.  .  .  (Scarce.) 

WATSON.— A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds, 
Ivory,  Bone,  and  Precious  Woods  ;  Dyeing,  Coloring,  and  French 
Polishing  ;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  By 
EGBERT  P.  WATSON,  Author  of  "The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON.— The  Modern   Practice  of  American  Machinists 
and  Engineers  : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow-work  generally,  with 
the  most  Economical  Speed  for  the  same  ;  the  Results  verified  by 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  floor.  Togethei 


HENRY   CAREY   BAIRD   &   CO.'S   CATALOGUE.         29 

with  Workshop  Management,  Economy  of  Manufacture,  the  Steam 
Engine,  Boilers,  Gears,  Belting,  etc.,  etc.  By  EGBERT  P.  WATSON. 
Illustrated  by  eighty-six  engravings.  I2ino.  .  .  .  $2.50 

WATT.— The  Art  of  Soap  Making  : 

A  Practical  Hand-Book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.  Fifth  Edition,  Revised,  to  which  is  added  an 
Appendix  on  Modern  Candle  Making.  By  ALEXANDER  WATT. 
111.  I2mo.  .  .  .  $3.00 

WEATHERLY. — Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
tallizing, Lozenge-making,  Comfits,  Gum  Goods, 
And  other  processes  for  Confectionery,  including  Methods  for  Manu- 
facturing every  Description  of  Raw  and  Refined  Sugar  Goods.  A 
New  and  Enlarged  Edition,  with  an  Appendix  on  Cocoa,  Chocolate, 
Chocolate  Confections,  etc.  196  pages,  I2mo.  (1903)  .  £1.50 

WILL.— Tables  of  Qualitative  Chemical  Analysis  : 

With  an  Introductory  Chapter  on  the  Course  of  Analysis.  By  Pro- 
fessor HEINRICH  WILL,  of  Giessen,  Germany.  Third  American, 
from  the  eleventh  German  edition.  Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle, 
Pa.  8vo.  .  .  .  .  .  .  .  .  .  $1.50 

WILLIAMS.— On  Heat  and  Steam: 

Embracing  New  Views  of  Vaporization,  Condensation  and  Explo- 
sion. By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated.  8vo. 

$2.50 

WILSON. — First  Principles  of  Political  Economy: 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization. 
By  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo $1-5° 

WILSON.— The  Practical  Tool-Maker  and  Designer: 

A  Treatise  upon  the  Designing  of  Tools  and  Fixtures  for  Machine 
Tools  and  Metal  Working  Machinery,  Comprising  Modern  Examples 
of  Machines  with  Fundamental  Designs  for  Tools  for  the  Actual  Pro- 
duciion  of  the  work;  Together  with  Special  Reference  to  a  Set  of 
Tools  for  Machining  the  Various  Parts  of  a  Bicycle.  Illustrated  by 
189  engravings.  1898.  .  .  .  •  «  .  *  #2.50 

CONTENTS:  Introductory.  Chapter  I.  Modern  Tool  Room  and  Equipment. 
II.  Files,  Their  Use  and  Abuse.  III.  Steel  and  Tempering.  IV.  Making  Jigs. 
V.  Milling  Machine  Fixtures.  VI.  Tools  and  Fixtures  for  Screw  Machines.  VII. 
Broaching.  VIII.  Punches  and  Dies  for  Cutting  and  Drop  Press.  IX.  Tools  for 
Hollow-Ware.  X.  Embossing:  Metal,  Coin,  and  Stamped  Sheet-Metal  Orna- 
ments. XI.  Drop  Forging.  XII.  Solid  Drawn  Shells  or  Ferrules ;  Cupping  or 
Cutting,  and  Drawing ;  Breaking  Down  Shell-,.  XIII.  Annealing,  Pickling,  and 


Cleaning,  XIV.  Tools  for  Draw  Bench.  XV.  Cutting  and  Assembling  Pieces 
by  Means  of  Ratchet  Dial  Plates  at  One  Operation.  XVI.  The  Header.  XVII. 
Tools  for  Fox  Lathe.  XVIII.  Suggestions  for  a  Set  of  Tools  for  Machining  the 


Various  Parts  of  a  Bicycle.     XIX.  The  Plater's  Dynamo.     XX.  Conclusion— 
With  a  Few  Random  Ideas.    Appendix.     Index. 

WOODS — Compound  Locomotives: 

By  ARTHUR  TANNATT  WOODS.    Second  edition,  revised  and  enlarged 
by  DAVID  LEONARD  BARNES,  A.  M.,  C.  E.     8vo.    330  pp.     $3.00 


HENRY   CAREY    BAIRD   &   CO.'S  CATALOGUfe. 


WOHLER.— A  Hand-Bookof  Mineral  Analysis: 

By  F.  WOHLER,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen.  Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated. 
I2mo.  $2.50 

WORSSAM.— On  Mechanical  Saws  : 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  $1.50 


RECENT   ADDITIONS. 

BRANNT. — Varnishes,  Lacquers,  Printing  Inks  and  Sealing- 

Waxes : 

Their  Raw  Materials  and  their  Manufacture,  to  which  is  added  the 
Art  of  Varnishing  and  Lacquering,  including  the  Preparation  of  Put- 
ties and  of  Stains  for  Wood,  Ivory,  Bone,  Horn,  and  Leather.  By 
WILLIAM  T.  BRANNT.  Illustrated  by  39  Engravings,  338  pages. 
I2mo $3.00 

BRANNT.— The  Practical   Dry  Cleaner,  Scourer,  and   Gar- 
ment Dyer : 

Comprising  Dry  or  Chemical  Cleaning;  Purification  of  Benzine;  Re- 
moving Stains;  Wet  Cleaning;  Finishing  Cleaned  Fabrics;  Cleaning 
and  Dyeing  Furs,  Skins,  Rugs  and  Mats;  Cleaning  and  Dyeing 
Feathers;  Bleaching  and  Dyeing  Straw  Hats ;  Cleaning  and  Dyeing 
Gloves:  Garment  Dyeing;  Stripping,  Analysis  of  Textile  Fabrics. 
Edited  by  WILLIAM  T.  BRANNT,  Editor  of  the  "  Techno-Chemical 
Receipt  Book."  2nd  edition,  in  great  part  re-written  and  much  en- 
larged. Illustrated.  293  pages.  I2mo.  .  .  .  $2.50 

BRAN  NT.— Petroleum . 

its  History,  Origin,  Occurrence,  Production,  Physical  and  Chemical 
Constitution,  Technology,  Examination  and  Uses;  Together  with 
the  Occurrence  and  Uses  of  Natural  Gas.  Edited  chiefly  from  the 
German  of  Prof.  Hans  Hoefer  and  Dr.  Alexander  Veith,  by  WM. 
T.  BRANNT.  Illustrated  by  3  Plates  and  284  Engravings.  743  pp. 
8vo-  #8.50 

BRANNT.— A  Practical  Treatise  on  the  Manufacture  of  Vine- 

gar  and  Acetates,  Cider,  and  Fruit- Wines  : 
Preservation  of  Fruits  and  Vegetables  by  Canning  and  Evaporation; 
Preparation  of  Fruit-Butters,  Jellies,  Marmalades,  Catchups,  Pickles, 
Mustards,   etc.     Edited   from    various  sources.     By   WILLIAM   T. 
BRANNT.     Illustrated  by  79  Engravings.     479  pp.     Svo.        $5.00 

BRANNT.— The  Metal  Worker's    Handy-Book   of  Receipts 
and  Processes : 

Being  a  Collection  of  Chemical  Formulas  and  Practical  Manipula- 
tion-; for  the  working  of  all  Metals;  including  the  Decoration  and 
Beautifying  of  Articles  Manufactured  therefrom,  as  well  as  their 
Preservation.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated.  i2mo.  |2  50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         31 

DJEITE. — A  Practical  Treatise  on  the  Manufacture  of  Per- 
fumery : 

Comprising  directions  for  making  all  Rinds  of  Perfumes,  Sachet 
Powders,  Fumigating  Materials,  Dentifrices,  Cosmetics,  etc.,  with  a 
full  account  of  the  Volatile  Oils,  Balsams,  Resins,  and  other  Natural 
and  Artificial  Perfume-substances,  including  the  Manufacture  of 
Fruit  Ethers,  and  tests  of  their  purity.  By  Dr.  C.  DEITE.  assisted 
by  L.  BORCHERT,  F.  EICHBAUM,  E.  KUGLER,  H.  TOEFFNER,  and 
other  experts.  From  the  German,  by  WM.  T.  BRANNT.  28  Engrav- 
ings.  358  pages.  8vo. $3.00 

EDWARDS. — American   Marine  Engineer,    Theoretical   and 

Practical  : 

With  Examples  of  the  latest  and  most  approved  American  Practice. 
By  EMORY  EDWARDS.  85  illustrations.  I2mo.  .  .  #2.00 

EDWARDS. — 900    Examination   Questions  and   Answers: 

For  Engineers  and  Firemen  (Land  and  Marine)  who  desire  to  ob- 
tain a  United  States  Government  or  State  License.  Pocket-book 

form,  gilt  edge          .        .  $1-5° 

FLEMM  ING. —Practical  Tanning: 

A  Handbook  of  Modern  Processes,  Receipts,  and  Suggestions  for  the 
Treatment  of  Hides,  Skins,  and  Pelts  of  Every  Description.  By 
Lewis  A.  Flemming.  American  Tanner.  472pp.  8 vo.  (1903)  #4.00. 

POSSELT. — The  Jacquard  Machine  Analysed  and  Explained: 
With  an  Appendix  on  the  Preparation  of  Jacquard  Cards,  and 
Practical  Hints  to  Learners  of  Jacquard  Designing.  By  E.  A. 
POSSELT.  With  230  illustrations  and  numerous  diagrams.  127  pp. 
4to-  $3-0° 

POSSELT. — Recent  Improvements   in   Textile   Machinery. 

Part  III: 

Processes  Required  for  Converting  Wool,  Cotton,  Silk,  from  Fibre 
to  Finished  Fabric,  Covering  both  Woven  and  Knit  Goods ;  Con- 
struction of  the  most  Modern  Improvements  in  Preparatory  Machin- 
ery, Carding,  Combing,  Drawing,  and  Spinning  Machinery,  Winding, 
Warping,  Slashing  Machinery  Looms,  Machinery  for  Knit  Goods, 
Dye  Stuffs,  Chemicals,  Soaps,  Latest  Improved  Accessories  Relat- 
ing to  Construction  and  Equipment  of  Modern  Textile  Manufactur- 
ing Plants.  By  E.  A.  POSSELT.  Completel-  Illustrated.  410. 

£7-50 

RICH. — Artistic  Horse-Shoeing: 

A  Practical  and  Scientific  Treatise,  giving  Improved  Methods  of 
Shoeing,  with  Special  Directions  for  Shaping  Shoes  to  Cure  Different 
Diseases  of  the  Foot,  and  for  the  Correction  of  Faulty  Action  in 
Trotters.  By  GEORGE  E.  RICH.  62  Illustrations.  153  pa.ses 
....  -V  '•'  .  .  .  |2.oo 


32       HENRY  CAREY  BAIRD  &  OCX'S  CATALOGUE. 

RICHARDSON.  —Practical  Blacksmithing : 
A  Collection  of  Articles  Contributed  at  Different  Times  by  Skilled 
Workmen  to  the  columns  of  "  The  Blacksmith  and  Wheelwright," 
and  Covering  nearly  the  Whole  Range  of  Blacksmithing,  from  the 
Simplest  Job  of  Work  to  some  of  the  Most  Complex  Forgings. 
Compiled  and  Edited  by  M.  T.  RICHARDSON. 

Vol.1.  210  Illustrations.  224  pages.  I2mo.  .  .  $l.oo 
Vol.  II.  230  Illustrations.  262  pages.  I2mo.  .  •  $l.oo 
Vol.  III.  390  Illustrations.  307  pages.  I2mo.  .  .  #I.oo 
Vol.  IV.  226  Illustrations.  276  pages.  I2mo.  ,  .  jjji.oo 

RICHARDSON.— The  Practical  Horseshoer: 
Being  a  Collection  of  Articles  on  Horseshoeing  in  all  its  Branched 
which  have  appeared  from  time  to  time  in  the  columns  of  "  1  he 
Blacksmith  and  Wheelwright,"  etc.     Compiled  and  edited  by  M.  T. 
RICHARDSON.     174  illustrations, #1.00 

ROPER. — Instructions    and   Suggestions   for   Engineers  and 

Firemen : 
By  STEPHEN  ROPER,  Engineer.     i8mo.     Morocco        .        $2.00 

ROPER. — The  Steam  Boiler:  Its  Care  and  Management: 
By  STEPHEN  ROPER,  Engineer.     I2mo.,  tuck,  gilt  edges.        $2.00 

ROPER. — The  Young  Engineer's  Own  Book: 

Containing  an  Explanation  of  the  Principle  and  Theories  on  which 
the  Steam  Engine  as  a  Prime  Mover  is  Based.  By  STEPHEN  ROPER. 
Engineer.  160  illustrations,  363  pages.  iSmo.,  tuck  .  $2.50 

ROSE. — Modern  Steam- Engines: 

An  Elementary  Treatise  upon  the  Steam-Engine,  written  in  Plain 
language;  for  Use  in  the  Workshop  as  well  as  in  the  Drawing  Office. 
Giving  Full  Explanations  of  the  Construction  of  Modern  Steam. 
Engines :  Including  Diagrams  showing  their  Actual  operation.  To» 
gether  with  Complete  but  Simple  Explanations  of  the  operations  of 
Various  Kinds  of  Valves,  Valve  Motions,  and  Link  Motions,  etc., 
thereby  Enabling  the  Ordinary  Engineer  to  clearly  Understand  the 
Principles  Involved  in  their  Construction  and  Use,  and  to  Plot  out 
their  Movements  upon  the  Drawing  Board.  By  JOSHUA  ROSE.  M.  E. 
Illustrated  by  422  engravings.  Revised.  358  pp.  .  .  $6.00 

ROSE. — Steam  Boilers: 

A  Practical  Treatise  on  Boiler  Construction  and  Examination,  for  the 
Use  of  Practical  Boiler  Makers,  Boiler  Users,  and  Inspectors;  and 
embracing  in  plain  figures  all  the  calculations  necessary  in  Designing 
or  Classifying  Steam  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  73  engravings.  250  pages.  8vo $2.<jo 

8CHRIBER.— The  Complete  Carriage  and  Wagon  Painter: 
A  Concise  Compendium  of  the  Art  of  Painting  Carriages,  Wagon*, 
and  Sleighs,  embracing  Full  Directions  in  all  the  Various  Branches, 
including  Lettering,  Scrolling,  Ornamenting,  Striping,  Varnishing, 
and  Coloring,  with  numerous  Recipes  for  Mixing  Colon.  73  Illus- 
trations. 177  pp.  i2mo 


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